Most of the manufacturers have designed a 'base' model carburetor, and then either find things to change, or have a request from a buyer for specific 'things'. To differentiate the original model, such as 'WT-827', from the new 'different' carb, they will add a suffix. Some will use letters, such as the 'A' found in the picture. Some will use a '-' [dash] followed by some numeric, depending on how many mods they expect to make to this carb. For example, it could start out as an 827-00, proceed to 827-01, etc. The scheme depends on the maker.
If you cannot find the kit with the 'A' suffix, buy the one without. I'd be you will find all the bits and pieces you need. Some of the differentiations could be in the throttle connection, the bellcrank, the arm on the end of the throttle shaft, choke mechanism, and even jetting. Most gaskets and needle & seat valve and check valve will work the same for all the suffixes used. When there is something 'different', the carb kits will indicate that, by indicating that 'this kit covers models up to -AA suffix' and if you have a -ZZ suffix, don't get that particular kit. Of course this could all be hot air, depending on who made the carb.