I was on 617 at Scampton in the early 60s and our hangar was 2 hangar. Second from the right if viewed from the airfield side. I always understood it had traditionally been 617's since first allocated in 1943 - even on their return from other wartime placements (Coningsby, Woodhall Spa etc.).
Gibson's office had been upstairs on the left as you looked at the side of the hangar. The CO still occupied that office in my day. As a lowly J/T I never got to see inside that Holy of Holies but the orderly room clerk swore the dog's scratch marks were still on the inside of the door.
In font of said offices was a narrow road into the hangar that led down from the original peri-track. The peri-track had been moved out into the grassland and concreted to accomodate the V Bombers when the base was developed in the 50's. The old peri-track was used as a carpark. Walking from the hangar to the peri, the dog's grave was on the left about 3 yards from the end. It was covered with a white granite (might have been marble) slab that gave the dog's name, Gibson as his owner and the date it was killed - pointing out it was the eve of the raid.
The squadron dispersal was E dispersal - immediately in front of and across the peri-track from the hangar. Going from the dispersal to the Airmens Mess for duty supper or the Naafi for last orders, one took a bee-line across the front of the hangar into the domestic site - straight past the grave. Returning was, of course, likewise. I have to admit that your correspondent did, often, witness certain airmen take a piddle on the grave as a matter of ritual. Naturally, I, as a refined member of the Avionics department, never resorted to such behaviour - we left that sort of thing to the riggers, plumbers and such like.
As it happened we had an engine fitter Ch/Tech who had served on 617 during the war - but not at the time of the Dams Raid. He categorically insisted that it was common knowledge when he was first on the squadron that, in fact, the dog had been left in the guardroom yard when it was killed and that night F/Sgt Powell detailed 2 airmen to go and get it and bury it. They took it over the road in front of the camp gates and buried it in the spinney. They then realised chiefy might want to see the plot so they scampered up to the hangar, scraped of some turf and churned up a couple of inches of earth.
For the really gullible, there is actually a book about haunted airfields in Lincolnshire and it claims that the ghost of Nigger has often been seen around Scampton - I must admit I'd never heard that story on either of my tours at the base. - But I was once trapped in a Vulcan while an escaped police dog was wandering around loose on the pan - stupid bloody dog-handlers!