Look how thick these are in second photo.
These are in Tucson, AZ. $50 plus shipping, probably 5 bucks.
Also have a like new Midwest Industries Scar M-LOK rail extension. Like to get $130 or best offer. I'd let both go for $150 plus shipping. I have the M-LOK rails that came with the extension, but they are nowhere near the quality of the PMM stuff.