Today's market on SKS's is in flux. I have bought/sold a few recently and am market savvy about looking at gun show prices, Gunbroker/auction prices, etc., and try to be thorough.
1) The past hierachy about production locale is breaking down. Used to be: 1) Russia 2) China 3) Yugoslavia (other makers so marginal in overall numbers - Romaina/Albania - they don't fit into the main stream pricing).
Now, it seems to recognize the facts 1) Russian production was very good 2) Chinese quality was OK 3) Yugo production was outstanding, just the weird grenade launcher features made it non-standard.
2) Paratrooper Chinese, and the Chinese mag, still carry a premium.
I would place the 20rd. Chicom mags at a $30 premium over standard mags, and the para version barrel at a $75 or 100 premium.
So, to value you your gun, I'd say if it were mine and I were to sell it, I'd say a good used version, with the 20 rd. mag (+30), Para barrel (+100), but missing the original bayonet (-50), would equal about $400.
SKS newbies might value it higher as a para and a Chinese, but saavy buyers will value it lower as a) missing the original mag, b)missing the orig mag. c) being Chinese and not Russian or Yugo where production standards were higher.
However, based on what you want - you should be able to trade or sell it for enough to buy a superb Mauser or Enfield - SKS's have appreciated dramatically vs. those two over the last few years.