Stamped brick at the Assistant Manager’s house

My sister-in-law Mily and I were exploring the ruins of the Assistant Manager’s house and it was there she discovered an engraved concrete slab. At least we thought it was a concrete slab at the time. It is stamped “Rawyards Glascow”.

Later, I found other images on the internet showing this identical stamp and they are all on bricks. I did some research and found that Rawyards Brickworks were located in Airdrie c1893-1940s. So on examining my photos again I am wondering if what we thought was a concrete slab is in fact a large brick embedded in concrete. A further examination would be needed to confirm this but I think it likely.