I was wondering if one can obtain an A back cover to replace the missing one below. If so, how much?  If not, are non-A covers available?  Price?  If not, can the tuner be replaced with a matching one?  Again, how much?
 
Thanks,
 
Bill, tgo

Covers are not available - you get the replace the whole tuner. These are around $25 for a single, and we have them in stock. Order as a Left-side Chrome.

Thanks, Mica.  Do the new ones have the A on back?
 
Bill, tgo

Ours do  
And they have the correct shape to the post and the key. These are the ones we have custom made for us by Gotoh. We like this style.