Para FALs where only originally made on metric rifles. You will not find any inch para parts as they never made an inch para.

You will have to use a para metric lower receiver assembly. You can use that with your inch barreled upper. However, the inch rifle uses a taller sight system compared to the metric. So you will need to use a inch rear sight, not a metric one.

 

IIRC the Para rifle has a different recoil action spring or somethign like that.

Sarge can enlighten us on that more.

 

The standard FAL or L1A1 has a recoil spring tube that runs from the lower receiver thru the length of the buttstock. The bolt carrier on these rifles has a rat-tail rod attached to it that presses on this recoil spring. This making a folding stock not possible.
So FN redesigned the recoil system and removed the recoil spring tube completely. They put the recoil springs above the bolt carrier just under the top cover. The carrier was redesigned with a tube built ontop of the carrier that the recoil spring rides in. This enabled them to but a folding stock onto the lower receiver.