Well I did find two posts saying that it was good to go and would just fire in semi auto in the A position. Factory selectors are 100.00 though. Alot of money just for looks 
Yeah it was a bit pricey for me also, but I wanted to build this as real looking as possible... even better that will actually switch to and function in the A setting, even though it is only semi autoWhile I would like one or two for myself, $100 for a $5 part is too ritzy for my blood.
My know. But my intent is to only say the PS90 is semiauto only no matter the generation of the trigger pack.
I don't mean to say anything more or imply anything more.
OP, I just did a quick check online for the safety switches and only the FNH OEM P90 three position switch is there.
From this, I sm hazarding to say the $100 option is the only option.
Three position switch + your Gen 3 pack = semiauto only on both firing positions.
I shoot by myself and as my momma told me... I Don't talk to strangersIt's your rifle and is completely legal but, I have to agree with the individuals that it draws unwanted attention. I can attest to the unwanted attention part. I went to my local range with my HK UMP conversion with full auto lower(It was semi though) and the owner was a former police officer and I wound up spending an hour explaining how it was legal and showing him parts diagrams on my iPhone. PITA. Luckily I was able to get a FBI lower (Sage/Semi) and sold the other one. Though the P90 F/A selector is not really seen like a black HK UMP with bright red bullets.
Eh... i'll just spend the money. The time I would spend trying to locate all that stuff and the time to do it and probably mess it up anyway, i'm better off just buying the real thing.A $5 selector, a file, an embossing stamp (Scarlet Letter of course) and a red crayon works wonders.
You must live by better ranges. I have 3 ranges to choose from. The closest range I was shot in the shoulder, the second closest has basically no ventilation system, you can't see your target past 30 feet because of all the crap in the air, and you NEED to take a shower after being in the box for more then 10 minutes. The third indoor range is actually really nice, ventilation system is so powerful you can spend all day in it and when you blow your nose no black crap. They even have huge wash sinks with lead removal soap. 100% state of the art.......BUT they check every gun, if NFA the paperwork, the ammo, the safety glasses, the hearing protection. All your stuff has to meet spec. You can't even use ear plugs. If you have a NFA weapon or something strange they call the manager/owner who is retired local police. He's got that know it all, I am the authority attitude which comes off as the type cast small town assh0le police officer. I wish I had an outdoor range close by, but I live outside of Atlanta in the suburbs. Luckily my family house a summer home on a private lake in the middle of know where in Pennsylvania. The UPS driver knows me by name because he delivers ammo and targets a least once a week. I remember him asking me WTF is in the box that do heavy, so I showed opened it and it was full of ammo. He smiled and said keep ordering so I can come out here in the middle of no where and have a relaxing day. Now I have to back researching how I can float huge 1" thick AR500 steal plates on a lake without tipping over or sinking.
Maybe said agents would like to weigh in on the matter? There opinion is really the only one that counts. My thought though is, semi auto is semi auto no matter how you look at it. I could have a 30 position switch, bit if it only fired in semi auto in all 30 positions it breaks no laws?Feel free to do as you wish, as you will be responsible for your actions.
Interesting you should mention the possession of said hammer packs, as not too long ago there was an individual with one, a PS90 SBR, a video camera, and a you tube account who did cross over into that area. He hasn't been seen here on FNF in quite some time.
One last bit of insight. FNF is open to all members, including but not limited to agents of the BATFE.
For the record, Stryker Enterprises will not be supplying you with a few screws a plate and some steel so you can convert a .30-30 lever action into a machine gun.