Are these throttle position sensor voltages a concern?
yes. they are off a tad. more accurate to test via ohms. the values for the "orange dot" TPS are...as per Ray in OZ who is a genius with these things: That measures 4.08K ohms across the sensor.
Measuring from the sensor moving contact that measures 566 ohms at the butterfly fully closed position and goes up to 3.817 Kohms at fully open open.
2008-2010 XB and all 1125 TPS units the same. part # is buell P0279.5aa
best price around
https://www.ebay.com/p/Buell%2D1125%...=nc&opts=opick
Is it also possible to have a failing O2 without it throwing a code?
yes....but extremely rare.
service the IAC assembly. i've written short simple write-up on here on how to perform same. typically doesn't fail or need to be replaced...but it is a good idea to service it.
redundant.....but....in all likelihood yet ANOTHER fuel pump requiring service/rebuild. cold start repeats....warm idle stalling....long crank-to-start episodes....lazy throttle response....back-firing thru TB....loss of power....all signs and symptoms of a failing pump.