5009 and 5010 were originally Comet IV cars. 5009 was owned by MTA and 5010-5029 was NJT. Then MTA sold their two Comet III cars (5179 and 5180) and their one Comet IV car (5009) to NJT. As a result, former MTA Comet IV cab car 5009 and NJT cab car 5010 became 5030 and 5031 (5030 being the MTA car.) This was done to make room for the two Comet III cavs so all of the Comet III cabs could be together in one number block. So thus, former MTA Comet III cabs 5179 and 5180 became NJT Comet III cabs 5009 and 5010. That is why 5009 and 5010 have the numbers on differently and the oversized NJT logo in front as to cover the MTA logo. Also, on current NJT Comet IV cabs 5030 and 5031, if you look at the lighted number board on the side near the cab on both sides, you can see that the numbers are of a different font than the other Comet IV cars. This is because the numbers had to be changed and they used a different font.
And also, all Comet III cabs and all Comet IV cabs have the tiger stripes. This is to make the cab more visible. Some Comet I cabs also have the stripes. The stripes were first introduced on the ACL. I believe the story goes that on the first NJT trip on the NJCL, there was a terrible accident with a car. So, at the time, Comet Is were being used on the ACL so a handful of them were painted with the stripes to make the cabs more visible. I personally like the stripe scheme on the Comet I cabs. Makes them look a lot more interesting. After that, NJT chose to purchase the Comet IIIs and IVs with stripes. The Comet Vs orignal design showed them having stripes but as you can see, they didn't get the stripes.
EDIT: You can also see where the MTA markings were on the side of the car on current NJT C3 cabs 5009 and 5030. I don't think though that current NJT C4 car 5030 (which originally was owned by MTA as 5009) has any MTA markings visible on the side. Could be wrong about that though. And also, my current avatar is NJT Comet IV cab 5031. This car was orignally NJT car 5010. I know, it isn't easy to understand all of this at first site.
Here is another avatar of mine I sometimes use of 5009:
You can see the oversized NJT logo and that the number not on the door like 5000-5008 but rather by the left ditch light. 5010's cab though has the number on the left but a about a foot above the ditch light.