If newer production, be aware that "MU96XX- MU97XX" had a piston defect (chewing up the blue O-ring when attached and removed) and will need to be replaced by KAC.
Tony
Can you PM me the full SN for this?
https://www.hkproshop.com/forums/threads/firearms-reference-data.33/
All information is strictly confidential.
Thanks.
Tony
PM received--- thanks.
Appears to be correct--- factory MP5's that I have seen (1966-1973) were parkerized, while 1974+ were paint over parkerization.
The various paint shades included shiny black (1974-1976), blue-gray (1976-1983), "matte" black (1984-1988), and "deep" NATO black (1989+).
Tony