Of course, such rumors should always be taken with a grain of salt. for example, the image which is supposedly from T-Mobile UK internal system still lists the iPhone 3GS, while the UK carrier does not sell it anymore.
T-Mobile is currently testing its LTE network, but of course, smartphones can always fall back to HSPA+. However, this would mean that the iPhone 5 is a pentaband (or more) phone as only a handful of smartphones work on HSPA+ bands from T-Mobile and AT&T – the Galaxy Nexus was the first to do so.
This would be in line with the rumors that the iPhone 5 would support LTE globally, a rumor that we suspect to be very exaggerated as no LTE modem can support more than a handful of bands. However, the iPhone 5 can easily be a global HSPA+ smartphone, if it is pentaband.
Finally, it is quite obvious that Apple needs to address every market that it can, given how competitive things are getting with Samsung. The Galaxy S3 has done extremely well and has addressed virtually every major market and carriers. Apple simply ignore this. Our take: T-Mobile USA will have an iPhone 5.