There are 3 models of PTR-32
Gen 1 - with/without rail. 93 length handguard. Very mag specific
Gen 1.5 - parked finish, green furniture, 91 length handguard, rail
Gen 2 - painted finish, black furniture, 91 length handguard, rail.
The gen 1.5's are a late 2014 run, before the gen 2 release. According to chris at PTR, they are identical to the gen 2's.
(New barrel contour, new locking piece, new bolt, new magwell latch.) They just have the older receivers, still with the CT and ptr-91 receiver marks.
They were basically a run of about 100 or so, for williams shooters supplies, and using up the old stock of receivers before the gen 2 launch.
So basically, if its got a HK91 length handguard, its gen 2.
(Hk91/g3 length, only leaves about 3" of barrel exposed after the handguard. 93 length, leaves about 7 inches exposed)