billflippen - You should be able to talk between those 2 VLANs using the 1638. Could you post the 1638 configuration for us to review as well as the 1638 route table? (Please remember to remove any sensitive information).
Please do not hesitate to let us know if you have any questions.
I had contacted Adtran support and they were insistent that the telco had not built the route in the MPLS.
Adtran was correct.