Gasoline fuel pumps tend to be "ignition" protected no matter what the application, land or marine. It isn't like alternators, where the marine models have additional vapor-ignition protection. I suppose a pump designed for the land market might have a nice aluminum casing which promptly pits away in salt air, but I don't think an insurer would bother looking all that closely at whether a pump was USCG approved, the claims value on any old boat with an A4 in it just isn't going to be all that high. (And the pump maker could be held liable in any case.)
I'd have to agree with cpaul, that's not one to lose sleep over. But like anything on a boat--and all too much of anything in stores these days--you need to eyeball it and see if it has been built right for your needs.
I'd disagree on the starting fluid, though. Flammable vapors below? No need, just spray the same areas with Windex or plain water, if the engine speeds up then stumbles it has ingested the spray. (Speeds up as the water blocks the leak, stumbles as the water gets into the cylinders.) Some mechanics also use propane from an unlit torch--which works the same as starting fluid, more or less. Still a flammable gas problem on a boat, I'd prefer the spray bottle.
USCG approved Windex, of course. (VBG)