Effect of pre-award Q&A on future claims

I've inherited a contract where bidder inquiries were published and answered on FBO.gov, but most Q&A did not result in an amendment to the solicitation.

Now the contractor is refering to some of the Q&A during the solicitation phase as evidence for their justification for a claim for equitable adjustment. I don't believe the published Q&A bind the government unless they are incorporated into the solicitation, but I'm looking for something in FAR or a GAO decision, or elsewhere that backs that up, and I can't find anything.

Any helpful references would be appreciated.