Have not received a 1099 from Zazzle; amount entered is correct, based on my records. Zazzle says 1099 should be received NLT 03/31/17. I have no choice but to wait?

It's best to wait unless you have all of the details from the 1099 exactly as it's reported to the IRS.  If not, you may end up amending your return later. 

Thank you for responding; I appreciate it. You confirmed what I thought, but I wasn't totally sure that there could be another avenue. I'll just wait.

You're very welcome!