well for everyone who knows the problem of finding his old friend and recognising the backdoor got lost or is broken.
i measured all parts and remodeled it in Solidworks.
it really fits perfect, i was deeply surprised. it looks like new.
have fun and keep your gaming alive!
P.S. one corner is slightly bend, this is because i was messing up the slicer a bit. just print it like any model. Supports needed, but very small and nice to break up. Resolution 0.2 is fine. i printed in PLA, but ABS would be much more reliable.