Hi, some thoughts regarding early short rail 75s serial numbers.
I've checked many models on internet (forums, auction houses) and this is my conclusion.
All '75 and '76 models have 01xxx serial numbers except first prototype batch (00001...). The highest '75 serial number I found was 01072, which is contradictory to number of CZ75 produced in 1975 (54). Nevertheless I assume that those pre-serial production pistols were labeled 01xxx and the true serial production started with 10xxx.
The serial production as mentioned started in 1977 and all '77 models have numbers from 10xxx to 12xxx, lowest I found was 10334, highest 11xxx. This is more or less in line with 2000 early short-rails produced in 1977.
Lowest 1978 number I found was 12493 and I guess they were numbered till 18xxx.
1979 models were numbered till 24xxx (I found one '79 with serial 19xxx).
As mentioned on this forum, short-rail were produced till 1980 with highest known serial number 256xx, which is in line with my assumption that the counting started at 10000. There were 14.697 short-rails produced from 1977 till the end of 1979, so the first short rail produced in 1980 should have serial number 10000+14697= 24697. So there were arround 1.500 short-rails produced in 1980, the rest of 9.000 were pre-Bs.
First pre-production batch with serial numbers 010xx
Production batch with serial from 10000.
1977- 2,000 produced with serials from 10000 till 12xxx
1978- 6,047 produced with serials from 12xxx till 18xxx
1979- 6,650 produced with serials from 18xxx till 24xxx
1980- ~1,500 produced with serials till 26xxx