Rabies vaccine?

Hi all, and thanks for all the wisdom here. I'm just two weeks post diagnosis, and am learning a lot from you. My Sammy is 11 and was diagnosed with diabetes 2 weeks ago. His blood glucose at the vet's was 740, then 530 on a recheck a week later. Hes doubtless been diabetic for some time - I missed the clues completely.

We changed food first - he was on all dry food - and he's adjusted well. He's eating Fancy Feast pate, and I am going to add Friskies pate next. My vet is great, and very supportive of this forum and home testing. The plan was to have me get good at testing 2X day, 12 hours apart, , then start him on insulin (I think Lantus) this coming Friday. His numbers at home range from 317-531, using an Alpha Teak meter the vet gifted to me as it had been donated. (I am a retired senior living on not much, and told her $ was a concern).

This all started because I took him in for his rabies vaccine, but somehow with the diabetes drama we didn't get the vaccine. My landlord requires it. Shall I ask the vet to give it to him Friday, when we start the insulin? Or is that too much for his system? I will of course ask the vet, but wanted some feedback from you fokks. Thank you!