Sorry for arguing bro but this is not the HK GMG, not as far as i can see.
Let me point out some visual differences. Look at barrel position, the one you posted with Pakistan police have barrel on the bottom edge (almost). In HK it is right in the middle of main body. Even the barrel shape, flash suppressor, mount and rails are different (at least they look different to me). A more close resemblance to Mk19 but still . . . . .
See the barrel seems to be at the bottom edge of the main body.firing assembly.
Different here: (also not the grab handle on top of barrel missing)
View attachment 401063
I may be wrong and just confusing the image angle. HOWEVER, compare the one being used by our police with THIS:
EXACTLY the same right?
Look at the barrel shape (with cuts), flash suppressor, the placement of barrel, the support (triangular protruding from on left side under the launcher)
The images you shared are of Noricon LG3 Automatic grenade Launcher that we use.

Plus we know that we use these already.
@TheOccupiedKashmir @Bilal Khan (Quwa) @Dazzler @The Eagle @TaimiKhan