is original i797 required for h1 stamping?

I went to US in h4, then filed h1 from there. Got h1 approved and started working from nov 2014.

Filed a new LCA and got the h1b amendment approved. I am yet to receive the docs from USCIS and I havemy h1 interview in 2 days.

Is original i797 required for stamping? Should I postpone the interview date to get the docs??

Please advice at the earliest

Its tricky. For a regular, no issue process, you must have the I-797 approval copy with your petition filing in order for you to consider your petition under non-CAP. BUT… there are cases where it was approved with partial information provided without the copy of receipt notice. Its up to the officer who is processing your petition with the information (like receipt number, validity dates of the approval etc) that you are able provide. But this is not guaranteed. At the same time its PERFECTLY legal to apply with the little known information, there will be no negative impact(as long as you didnt lie or misrepresent any fact in your petition).