I would assume they are both 1/4" NPT.
The only thing I think may be different would be the press cylinder size, which would change how the gauge reads if it shows tonage rather than PSI.
If you have a serial number their customer support may be abe to tell you.
here is a breakdown on it.
https://www.otctools.com/sites/default/files/100551_en.pdf
the gauge p/n: 16715 -$82.95
should be able to order from an OTC parts distributor. If you don't have one near you I would be able to drop ship one to you.