Besides which, after having both factories bombed the Stirling didn't enter service in large (more than a few squadrons) numbers until much later than first flights would indicate.
Belfast and Rochester, yes, and this undoubtedly had an adverse effect on production. Production was stopped by the 15th August 1940 raid and did not recommence at Rochester until March 1942.
However, Stirlings were also built near Swindon at South Marston (351). After the bombing of Rochester 27 aircraft were also completed at the Gloster Works at Hucclecote. The drawing office relocated to Kidderminster, which was sensible as substantial numbers were built by Austin Motors in Birmingham (620). Total production was only 2,383.
The Stirling staggered into operational service in February 1941, but in such low numbers, rarely more than a handful, they were hardly relevant.
In April two squadrons were operating Stirlings.
In August 1943 twelve squadrons were operating Stirlings, 146 serviceable and operational aircraft, 82 unserviceable.
The last operational use of Stirlings in Bomber Command was not until September 1944, though they hung on in a variety of support roles (at HCUs well into 1946) and in other non bomber roles.
As far as Coastal Command goes I can't even find a request for them to be operated there, which is odd, because the Command asked for just about everything else at some time!
Cheers
Steve