I don't mean to be the only dissenting opinion
but here goes...
I think you're making an even trade. Your SPR is a bolt action rifle that would not be subject to any potential assault weapons ban. The FAL, on the other hand, if an AWB goes into effect will end up appreciating to a much greater extent. Now, of course its speculation, but then again, the majority of opinions that you'll receive on this topic will be from the old-timers who remember when they picked up an FAL kit for $99, a receiver for $150 and were at the range for less than $400. They were also blasting surplus 7.62 for $0.10 a round. Times have changed.
An Imbel receiver goes routinely over $500. Some Gear Logo'd receivers have hit $600 on the bungroker. Then consider the price of a kit these days. STG kits are over $600, more if numbers matching and complete, Brit kits over $600 if you can find one with an unmolested barrel, and Imbel kits that look like ass are fetching $350. If you do a search on bungroker the only listing for an m444 has a buy it now of over $2000
??!!! (He must smoke a little crack)
Anyway, basically, I don't think a straight up trade is you getting the short end of the stick. If there is a new AWB and the going rate of an m444 becomes $2500, would you trade him back? No, you'd say you made "a wise investment" and tell him he shouldn't have given it away. The way I see it, FN will keep making SPR's, and they will always be available, the FAL on the otherhand, who knows...Whatever.