As a general note, NTLMv2 is an old protocol and NTLMv1 is from the stone age. So when refering to "NTLM" you usually implicitly mean NTLMv2. I'm not quite sure what your customer has in mind when he asks about NTLMv1 support. I hope he doesn't run devices that require NTLMv1...
If you need to actually show some official statement to the customer you can open a support case and ask the question.
Or start a packet capture, open a website that requires authentication with a realm that has only NTLM enabled and show the customer that indeed NTLMv2 is used.
What BCAAA supports depends on the configuration of the Windows server it is running on and setup of the AD domain. If NTLMv1 is disabled there (which is recommended) then of course BCAAA cannot support that.