Fits just fine, very light. - Tdi Arms Zastava Lower Aluminum M-LOK Handguards

The AK handguard fits just fine on my PSA AK-104. Note that I modified my factory front handguard retainer as it comes from the factory as a lot thicker than a COMBLOC retainer. I used a dremel to shave the inner bearing surface where it caps over the lower handguard. Other than that, the PSA front trunion has a different profile than the COMBLOC trunions. You must file these "nubs" that slot into the front of the receiver to avoid fouling on the truinon. The entire handguard is one piece aluminum and is very easy to file so GO SLOWLY. Also, file it at an angle so it gets tighter as it gets closer to being slid all the way into place. With this method you will have some leeway when going from "won't fit" to "too loose". At the end, I tapped it in the last 1/8" with a mallet and it fit nice and tight.
With respect to the sling swivel hole on the front, I noticed some sling swivels didn't lock in and some did, but I have chinesium and magpul/bcm/etc, so nothing certain on that front. Note that the swivel hole is only on the left side, not right.