Factory Proofed Inglis MK1 star With Odd Serial Number

[polkey]

Have had this Inglis for a while now and always wondered if anyone out there who has seen another or knows what it may be.
Other than the odd serial number nothing else really sticks out, fairly standard MK1* configuration with fixed sights & no stock slot.
The frame, slide & barrel are all standard proofed, the frame & slide with a stamp and the barrel with the engraved crossed flags (barrel proof is very faint/hard to see).
The frame serial number is D1011X and is stamped, not engraved as is normally seen. The slide is not serialized and the barrel serial number appears to have been applied with the same engraving process as the cross flags proof mark.
I don't think it's a lunch box gun as they are generally assembled with loose parts and are not proof marked, unless it was taken during/after the proofing, which is a possibility seeing as whoever added the proof marks to the barrel also serialized the barrel in the same way.
Thoughts?

 

[recce]

The R. Blake Stevens book that I have shows DP for Drill Purpose but not a single D. Might have been a miss-stamp.
I have the small Historical Arms Series book, the more in-depth Inglis Diamond book may have more info.

 

[canuck]

The known "DP" marked pistols were pantograph marked on all three parts and usually were not proof or acceptance marked - the serial on yours appears to be stamped
In the Inglis Diamond book by Clive Law, there is a picture of an Inglis with a serial of "D1" - again, pantographed in all three locations, very early slide script. Is says in the book that it was registered in 1945 to the head of Inglis security (Harold Waterhouse)
I'd guess yours is a lunchbox gun myself.

 

[polkey]

The known "DP" marked pistols were pantograph marked on all three parts and usually were not proof or acceptance marked - the serial on yours appears to be stamped
In the Inglis Diamond book by Clive Law, there is a picture of an Inglis with a serial of "D1" - again, pantographed in all three locations, very early slide script. Is says in the book that it was registered in 1945 to the head of Inglis security (Harold Waterhouse)
I'd guess yours is a lunchbox gun myself.

I don't believe it is from the DP series either for the above mention reasons regarding the engraved serial number.
I dont have a copy of the Clive Law's book to reference, I wonder if the serial numbers were engraved before or after they were proofed, if it is a lunchbox gun I would guess it was taken by someone in the proof house.

 

[npbra]

Lunchbox gun with someone's attempt at putting on an RCMP serial number to make it legal.