is the buffer tube used by the entry stock 6061 or 7075 aluminum?

Second question, there are a few companies that make adapters for fixed stocks that give you QD swivel sockets near the receiver, similar to the receiver end plates used by adjustable stocks.  Will these fixed stock adapters work for the RRA entry stock?

Both good questions that I don't have immediate answers for.
The AR0113T receiver extension used in the Tactical Stock is a short version of theAR0113B rifle receiver extension, but I don't remember if it's the same material.  I'll have to check with Engineering on that and get back to you.
GRSC used to make an A1 single loop receiver endplate, which IIRC worked with the Tactical Stock. I don't believe that kit is available from them any longer.  We have modified the A2 version that we carry (AR0144A) a couple of times...the screw has to be replaced with a customized A2 buttstock screw, and the stock spacer has to be reduced in thickness to approximately that of the endplate.
Steve/RRA

Let me ask another question then.

Is the entry stock's buttplate mount compatible with A2 buttplates? I understand you can't tell me about third party products but, theoretically, if you can mount an A2 buttplate then is there any reason an extra thick buttplate wouldn't fit? Getting the length up to 8.25 to 8.5 inches (same as a 6 position stock two clicks out) would be ideal.

For a sling I can drill and mount a QD socket if I'm feeling frisky, otherwise an A2 wrap around adapter can work.

You would need custom length screws, but yes, an extra long A2-style buttplate should fit on the Entry Buttstock.  I have an A2 plate (using an A1 top screw and no spacer) on the single Entry Buttstock that I have personally.
Steve/RRA

Two other questions then.

1) Did you hear from your people on the construction material of the buffer tube for the entry stock?

2) Using a regular sized buttplate, an A1 length screw is the correct length for the entry stock, correct?

@RRAMODERATOR

1.  6061 T6
2.  Yes, it should be.
Steve/RRA