Well, I gave up looking for the Op Specs. I went back the to the FOM and found the appropriate section.
Here's something that I think backs up what most of the posts have been saying:
• P-RNAV procedures apply to operations including departures, arrivals, and
approach phases (From Initial Approach Fix (IAF)/Initial Approach Way
Point (IAWP) to Final Approach Fix (FAF)/Final Approach Way Point
(FAWP)). Final Approach Segment and Holding patterns shall be flown
with conventional procedures.
• Type A, B procedure apply to departure and arrival procedures
• Pilot operating in a designated airspace as RNAV 1 or RNAV 2 shall
confirm the RNP value in the FMS matches with required RNP Value 1 or 2.
and this section:
■ Equipment required for operation in RNAV 1 area and
RNAV 2 area
• Effective Navigation Database
• One FD in NAV Mode
• Single FMC, Single (M)CDU, Dual IRU, Single ND
• Required Equipment should be accorded between RNAV 1 area operation
and RNAV 2 area
― Single GPS Receiver(inculding RAIM funtion) or,
― DME/DME Receiver or,
― VOR/DME Receiver *(1) or,
― DME/DME/IRU Receiver *(2)
To me it sounds like we were equipped and approved to do what I thought we were.
Maybe the company just decided (like many have noted) "It's the PRC. Don't do it without raw data."