How to ask for a sample size of primary antibody?

So, I'm interested in looking at a protein that's usually studied in developing mice post-natally, say from P0-P21. I'd be looking at this protein through IHC on P56 mice, which has little to no literature to recapitulate. Because of that, I'm a little worried about buying a whole new tube of antibody - it's around $400 dollars, and I'd be the only one using it. Plus, the validation experiments on the seller's website (ThermoFisher) have IHC in different tissue than what I'm studying (retinal tissue vs coronal cerebrum).

So, my question is - can I somehow ask for a small sample size of antibody? If you've done so before, how did you go about it/who did you contact? Thanks!