Yep, a USA player. Tested with "Extras Series 1" (PAL, UK, R2 -- many DVDs are R2+4 but not this one, it won't play in my Australian PS3), "Red Road" (PAL, Australia, R4) and "The Simpsons Movie" (PAL, Australia, R4). Also retested the SD-DVD side of "The Bourne Ultimatum" combo (NTSC, US, R1) to make sure the R1/NTSC side of things was still working.
The steps you set out are the ones I used. For people who have already installed the Region Management Test Mode hack I don't think they'd have to do it again and could skip steps 6-9.