Hi Eduardo,
These "A" suffix devices are just slight improvements over the non "A" versions.
A lot of the time they drop straight in and they are cheaper GB60 = $5.25/ GB60A = $3.95
Non "A" will probably dissappear.
Differences and how to handle them are detailed in EB652 and EB671 etc.
Refer to the appropriate product page for the correct one.
Regards
David