I don't know if this particular rifle will go up in price. But set aside collectability for a second.
Price is what you pay. Value is what you have.
A rifle made today with all wood and milled metal parts will cost you thousands of dollars. But we are blessed to buy a M48 for $600, a LE for $900, a K31 for $1000, etc. We are very lucky, very lucky. Are these going to be as accurate as modern CNC made hunting rifles or that $4,500 Blaser? Well, no. But milsurps work from jungle to arctic, and can take way more abuse than a modern hunting rifle in the same price range. Even the Mosin is completely reliable and that's quite a feat considering the awful wartime conditions when a lot were made.
Price and value get mixed up because wasn't long ago when Enfields were $100. But that's like me saying I remember when a house was $10,000 and therefore I'll never pay $350,000 for a house today. (I'm dating myself but I remember 10 cent chocolate bars, but we still buy them at $2.)
My point is milsurps have great utility because these old guns simply work and work, without ever complaining. You never worry about plastic parts breaking. That's great value to me. Your mileage can and will differ but I'm talking for myself only. And we haven't even gotten into the collectibility factor or the fun in taking these to the range.
Obviously enough people thought $900 was good value for the Semin at TradeEx. I don't know what the future price will be. That's a supply and demand question and I'm not smart enough to know the answer.