One person’s wood refinishing job is another’s nightmare. If you are wanting to sell, then it might be best to leave it as is, letting the buyer decide what he/she wants to do. Personally, I think it looks fine as-is.
While I prefer rubbed oil finishes, it would be wrong on an A-5, which probably left the Herstal factory with a light varnish. If you’re keen on refinishing it, I would recommend researching what the original finish was, and duplicating it as closely as possible without resorting to sanding, buffing etc. Once removed, material can’t be put back… Sandpaper and wire brushes are the quickest methods known to render a gun worthless to a collector, and it is the collectors who pay the highest prices.
The A-5 in sixteen, pre-“sweet sixteen” markings, is highly under-appreciated. I have the earlier version to yours, with the 2 9/16” chamber, and the safety at the front end of the trigger guard. For an auto-loader the standard 16 is not a heavy gun (at 7 1/2 pounds), and it handles beautifully.