1099R is in mail, but won't arrive by tax day - workaround?

By accident $168 was over-contributed to my 403b plan (switched jobs this year, apparently that can happen).  Contacted the plan manager and they said they'd issue a form for the (presumably1099R), but it probably won't arrive by tax deadline.

 

Is there some way I can anticipate this and just file taxes once, or do I have to file again when I ultimately receive it?  Thanks!