Some caveats need to be addressed...the first one being value is what someone will pay.

Also- it isn't an "Altec rack". It's a rack someone put Altec components in.
There is no value beyond the components.

I think you will find it almost impossible to get a high dollar figure for the complete rack. A buyer is only going to pay for the components he wants.The EQ probably has the highest value, but it will be to a small studio owner. Big studios are almost entirely digital. There are many very convincing digital plugins that emulate vintage devices. A big studio is likely to use these and avoid the maintenance hassles. Smaller "craft" studios are more likely to use the real thing.

My advice? Google the heck out of the components. There are likely prior sales.
But were it mine, I might advertise it as one piece to see if I get any offers. But they will likely be from flippers intending to break it up, and will be lower.

It's not like breaking up a speaker system. Altec didn't offer this set as a package. It was put together by a third party.