Baby weight?!

I had my 3D/4D sonogram about a week ago. I'm 32 weeks and 3 days. They told me they weren't allowed to tell me the weight because it wasn't through my doctor it was like a private sonogram company or whatever. Is there any way I can ask my doctor to give me a sonogram to tell me what his weight is?! I see so many moms who know the weight of their babies but I'm dying to know. Help please!