No go on the walk-in (will have to re-schedule work to make original appointment).
They were busy and down a fingerprint technician. A very nice IO was willing to re-schedule my appointment to a later, more convenient time but I told her I would change my work schedule. She could only re-schedule to a later time as they need at least 2 weeks to generate a new notice.
She couldn't find my current FP notice in the system (just my old ones from initial GC and removal of conditional applications) when she tried to re-schedule the appointment, so even if they'd allowed the walk-in, I'm not sure if they could have associated the FPs with the application properly!
Based on the fact it took nearly 1 month from application acceptance to FP notice, I think Portland DO is probably backed up, especially as the N400 non-military prending numbers have been increasing steadily since September and the average processing time is 0.3 months above national goal & average. By comparison, Seattle's pending numbers are pretty steady and I'm seeing fast processing times (around 90 days) based on forum posts.