No 7.62x39 parts have been produced anywhere insofar as I'm aware.
A member here posted about doing the Bren barrel replacement. Not too different from a SCAR if I recall.
Third, the law is however BATF decides to decide it. Based upon your reasoning, most AR15 owners could be found guilty of the same.
My reading of lastest big letter/ruling regarding SBRs last year, is that "intention" is what classifies a pistol vs an sbr. If you intend to convert any pistol to an SBR (without parts in possession, or in using existing parts like shoulder brace in way that "converts" to SBR by how you use them), then it is an illegal SBR... The SBR law these days is a complete morass. So long as you try to do the right thing you should be kosher. If you're doing other stuff where federal gun charges may be added to your offences, then perhaps be concerned. If not, ,you're probably safe not to worry. If wanting to be super safe, have a buddy keep parts in question in his safe (or bury them in your backyard, etc).
