Hello Jawhawk500. Happy New Year to you and yours. This morning I ran across an Ebay auction for the 2101's auxiliary tender (former NYC Mohawk) in HO scale. It clearly shows the top piece fabricated to cover the former coal bunker. I thought this might be of interest to you. Looking forward to seeing more progress pictures of your 2010.
HO Key Imports NYC Mohawk Brass Freedom Train Custom Auxilliary Tender for AFT1 | eBay