Well, the ammo is worth about $300+ at todays prices so that's a fairly cheap kit in today's market.
You can build it on a standard AK74 receiver using a standard AK74 FCG and selector. Easiest, but it will be missing the left side selector. Not "correct" but functions just like a correct one would.
You can build it on an NDS Tantal receiver that has the proper cutouts and spacing for both selectors that come in the kit. You still use the normal AKM FCG but the left side selector is installed and looks correct. IIRC, you can either leave it non-functional or rig it up as a left side safety lever.
AFAIK, the actual "Tantal" version always had the sidefolder stock. It fits into a normal fixed stock trunnion though, so replacing it with a fixed is just a remove and replace operation with no mods needed.