Thought I would let everyone know, while I was browsing Numrich for possible new forend wood (which they have by the way), it seems they have reproduction heatshield with bayonet adapters again in stock again - riveted not welded, blued and unmarked.
https://www.gunpartscorp.com/products/813820
They also have rear swivel sets, but there are no magazine plugs in stock.
After reading around over the last many months, it seems the Numrich ones (from previous lots) fit pretty good on model 97 solid or takedown factory original full length barrels (cut back), and model 12 factory original riot barrels. Cutback model 12 barrels, norinco 97 riot barrels, and original 97 riot length barrels may likely be no-go for these without modification and/or shimming.