If you purchase Alexander Murray's, death certificate from Scotlandspeople online this will confirm his wife's, name plus his parents names.
I think your Alexander, was a gamekeeper, and he most likely was not born in Dalrymple, Ayr.
It also looks like he was married to Sarah Cockburn Campbell, 26/Feb/1848. Dalry,Ayr.
As i stated you need his death certificate to verify Alexander, true identity.
This Alexander Murray, did have a son William Murray, do you have a age for William.