The wood stock and handguard are made by Altamont Company in Illinois for both Inland and Auto Ordnance. They use someone else to manufacture the folding part of the stock.
The thickness of the rivet heads are unique to these stocks.
Attachment 74826
Initially Inland's M1A1stocks were the same as Auto Ordnance. Those stocks, and those still used by Auto Ordnance, the handguard often doesn't align with the stock properly with parts of the handguard sticking out over the edge of the stock. Inland has been correcting this with theirs. Inland also stains the wood with the darker walnut stain where Auto Ordnance uses a much lighter stain.
Inland is now taking it a few steps further by having the metal finish darker than before and with those still used by Auto Ordnance. The buttplate had a copper color color to it, likely due to the make up of the metal used for the buttplate. Metal with a higher quantity of nickel requires a different temperature to get the dark gray/black color. Inland's newer finish appears to cover the copper color.
Below is what they look like disassembled. This example was purchased from Auto Ordnance as a replacement stock. The leather is glued onto the side plates and the exposed area around the oiler opening is sticky. The example below the leather had cosmetic flaws.
Two notes. First, the overall length of the wood of the forend and handguard have been slightly shorter than GI. This only becomes apparent if you switch out the handguard with one from another manufacturer and try to mount the barrel band to it. Second, if you are considering buying an M1A1 stock you might want to also have a look at those being sold by Fulton Armory. They use the correct brake line rivets. The finish isn't as dark. They are GI dimensions. Most commercial M1A1 stocks require a small amount of handfitting to the carbine.
Attachment 74827
Attachment 74828
Jim