I checked the bottom row of 1L and don't see a match either. But I still think the right stamp is a B relief with no guide dot, so probably bottom row or right column.
I'm not so sure the URDB is gouged out like 1L stamps, and the bottom margin is wide enough to make me try other bottom row stamps before trying other 1L positions. So the next place to try is the bottom row of 2L and 3.
Before finishing checking 2L I found a likely match at 92L2L. My eyes aren't what they used to be, so I'd suggest checking, then check at least the rest of the bottom row stamps from 2L and 3.
As for the left stamp, I assure you there are plenty of A reliefs on 5e, somewhere around 80. I may well be wrong about it being 5e, but that weak left inner line would make me start there. A very nice 3c 1851 plating reference is available on http://stampplating.com