The carbine stocks used by Inland and Auto Ordnance are made by Altamont in Illinois. I bought one of their first stocks maybe 5 years ago when someone clued me in to a new carbine stock maker and where I could buy the stock retail. That stock was way off spec.
Auto-Ordnance and Inland are well aware of the problems with the stocks/handguards made by Altamont. The offset barrel channel, the handguard/stock fit, 1/4" shorter than all others, etc. auto Ordnance I think buys a B grade wood as knots and knot repairs are acceptable to them. Not all have them but when they do it's acceptable. The darker finish used on the Inland stocks makes it difficult to tell if any of theirs have these too.
I bought one of these stocks from Auto Ordnance several years ago. They told me then the knot plug repairs were acceptable and tried to tell me the knots/repairs were also acceptable to Ordnance on the original carbines. I have a new Auto Ordnance carbine I'm running through my usual eval to see if anything has changed and what they're doing. No repairs but a number of knots. Only relevant to Inland as they get their stocks from the same manufacturer and have had many of the same issues.
The Auto Ordnance I have at the moment I sent back due to the overlap of the handguard being too much. I also requested they machine the nose rounded instead of omitting that step. When it was returned they handguard fit was as it should have been in the first place. They did not round the nose.
To Inland's credit they have made some efforts to correct some of the stock issues. Such as the extra concave cut in the slingwell so the sling with oiler will fit. The stocks used by AO the sling/oiler doesn't fit and isn't included.
Since Altamont uses a CNC machine I don't understand why they don't just correct these issues once and for all. I suspect it may have to do with costs/profits that don't support making a better quality stock and handguard.
Jim