I have two M48s - one I ordered from Aim Surplus awhile back, the other I bought at Big 5. Both are virtually (if not actually) new. My guess is that neither had ever been issued - they both show only very minor marks - probably from handling during storage, etc. They both came with nice bayonets, slings, and all accessories. I think $160 is a good price for rifles in this condition. I think I've seen them advertised recently for around double that. I know dealers can order M48s for less from some sources (maybe $110 or so), but I suspect that these have a little more use and/or don't come with all the accessories. The one I ordered came with a patched stock (where a piece of wood had been inserted - probably to replace a knot or defect in the wood). The patch was well done, probably when the stock was first made, and has no effect on functionality - but it does hurt the cosmetics a little. When you buy one at Big 5, you can see what you are getting up front. And by the time you add in FFL fees, shipping, etc. I don't think you'd save much by ordering. I'd go for the Big 5 rifle.
By the way, I must admit that I haven't gotten around to shooting mine yet. I plan to save the one I got at Big 5, and shoot the one with the patched stock. They do seem like nice, well-made Mausers. I believe the action is a little shorter than the more common Mauser K98, so I suspect that it would be tougher to find drop-in replacement stocks, and maybe scope mounts and other accessories for the M48.
Doug