Do you mean NOS as opposed to new production?
The DM 36.5 uses 6h30s. There are NOS options for those tubes which could be an upgrade but they are very expensive, about $500 a pair. Those would be the 6H30DR. Be careful buying these since there are a number of fakes out there. The rectifier is a 5AR4 which can easily be upgraded with any Mullard GZ34. Modwright recommends doing that.
I haven't read much about the PH150 but any component which uses 6922s can be tested with NOS versions, usually with positive results.