The 5000A is the large-capacity version of the original Ambassadeur 5000: the same Swedish frame, gears, star drag and level wind, but with a deeper spool for anglers who wanted more line on the reel. The A suffix marks that bigger spool, not a faster gear.
ABU built it from 1955, and it first appeared publicly in Garcia's 1957 American catalogue. Like the plain 5000 it runs on bushings rather than ball bearings, so it is a simple and durable reel to clean and service.
Most surviving examples are red, Swedish-made and stamped on the foot. It is thinner on the ground than the 5000 or 5000C: our latest snapshot found only about a dozen matching listings, with loose working reels around $50 to $90 delivered and boxed or cased sets around $120 to $230.
None of those listings described a serviced reel, so plan on a clean and fresh grease whichever one you buy. Check the spool carefully, because it is the part that makes the reel an A and swaps between 5000-series reels are easy.