Yes. The AT-1108/ARC will directly replace the original Collins 37R-2U. Although there is no official documentation stating their interchangeability, one can view the functional and physical specifications for each and determine that they are exactly equivalent. Both have separate coax connectors for VHF and UHF connection. Both have the same hole patterns or footprints.
Most importantly, a New condition RA Miller AT-1108/ARC is available at a fraction of the price that the Collins 37R-2U is available on the used market. It should be noted that some of the used 37R-2U available on the market could be over 30 years old.