While the SKS-M is originally made to utilize AK mags the one you are interested in is the late "post-Ban" version. this has no bay lug a funky block where the cleaning rod goes in and "some" have had issues with slam firing. I wrote some as not all of them did or do for all you thumbhole sks owners.
The TH stock or any SKA using ak mags will not be a swap for any standard or aftermarket SKS stock, different magwell, trigger group set up.
For $600 you could get a basic SAR / WASR 1 some mags and ammo OR build your own AK for say $300 average
here is one looks like it gas already been spoken for YMMV
http://www.co-ar15.com/forums/showthread.php?t=40457