Is there a decoding legend for PMG’s Catalog #s (Fr#)? 0

[MrLRJenkins]

Can someone point me in the direction of what the suffix means behind some of the catalog numbers PMG has on their site? 
For instance: what do the following suffixes mean:

”s”

”bpe”

“SOI”

I’m sure there’s others. I can’t find an answer anywhere. 
 

TIA

[Fenntucky Mike]

On 8/17/2023 at 8:15 AM, MrLRJenkins said:

Can someone point me in the direction of what the suffix means behind some of the catalog numbers PMG has on their site? 
For instance: what do the following suffixes mean:

”s”

”bpe”

“SOI”

I’m sure there’s others. I can’t find an answer anywhere. 
 

TIA

s = specimen, usually

bpe = back plate error, I believe

SOI = Super Orlof Intaglio, a printing press

There is no "legend key" that I know of to decipher these but it's easy enough to go to a site like Heritage Auctions and type in the Fr. 1908 and browse through to try and find a match for Fr. 1908-Hbpe, for example, and read the descriptions. The reference Paper Money of the United States should also have the corresponding Fr. # and probably a short description of what they mean.