No, I identified the changed bytes in the GOG executable. Then I introduced this changes into the keeper-klan-mirrored-unlimited-zoom-exe. And this exe with unlimited zoom works now with the GOG installation.
(to backport the zoom changes e.g. to 1.3 someone has to identify the changed bytes against a zoom unmodified 1.7)
[EDIT]
I found the bytes, a JG overwritten as said by darkbytes (tested for 1.8 and 1.7).
Unlimited Zoom bytes (first 2 bytes)
GOG 1.7 / normal 1.7 / 1.73 / 1.80
GOG-1.7.exe ( 2.977.280 bytes)
0x00490D1 7F -> JG (2-bytes opcode, following byte adress)
0x00490D2 02 -> relative address
0x00490D3 8B -> move
0x00490D4 FE
Zoom-1.7-exe etc.
0x00490D1 90 -> NOP
0x00490D2 90 -> NOP
0x00490D3 8B -> move
0x00490D4 FE
1.3 (unchecked!)
DKII_1.3-exe (size 2.922.496 bytes)
0x0041EC2 7F
0x0041EC3 02
0x0041EC4 8B
0x0041EC4 FE
DKII_Zoom-1.3-exe
0x0041EC2 90
0x0041EC3 90
0x0041EC4 8B
0x0041EC4 FE
1.3 (unchecked!)
DKII_1.3-exe (size 2.922.496 bytes)
0x0041EC2 7F
0x0041EC3 02
0x0041EC4 8B
0x0041EC4 FE
OR
DKII_Zoom-1.3-exe
0x0042051 90
0x0042052 90
0x0042053 8B
0x0042054 FE