I simply googled the model numbers and got this:

https://www.agilent.com/store/en_US/Prod-G2581-80001/G2581-80001

This basically means that identical part to G3170-80001 is now G2581-80301. Hope this helps you.

Thank you very much for the information.

They might indeed be interchangeable but what the above link shows is that G2581-80001 has been replaced by the G2581-80301. The G3170 - 80001 is still a current model. In all likelihood they could be interchangeable if there is no change on the pin positions for the connectors and what is inside the housing is the same. If you want to be thorough, I would contact Agilent support by their toll free number and - while they'll take a day or so to talk to their engineers, you will typically get a response. Have the serial numbers of the instrument(s) handy because they always ask that first.

Of course, if you already plugged it in and are reading the expected pressure feel free to disregard the above!