question about my mark IV head

[Fronzil]

notice how the 'boogie' label is on the bottom right, not top left of the grill??

pretty sure its a mark IV B head (detachable power cable, and the switches on the front by the output level/silent recording knob are for the B im pretty sure..did they move it down on the B? or is it probably just the previous owner moving it?

 

[MrMarkIII]

notice how the 'boogie' label is on the bottom right, not top left of the grill??

pretty sure its a mark IV B head (detachable power cable, and the switches on the front by the output level/silent recording knob are for the B im pretty sure..did they move it down on the B? or is it probably just the previous owner moving it?

No.
The way to tell if it's a "B" is the effects loop configuration. The switches are on the front of all "long" head chassis (as opposed to on the back of the "short" combo chassis). Detachable power cable does not define a "B" either. Somebody, not Mesa, most likely an owner, moved the badge.
This is what the back of a "B" looks like:

Note well how the effects loop jacks are configured. The "A" version jacks are in more of a rectangular pattern.
Hope this helps

 

[Fronzil]

detachable power cord indicates its a LATE 90s B..sorry i should of specified..some early B's didn't have the detachable cord, but the late ones do..so basically i was right, if the cord detaches, it has to be made in the late 90s, therefore guaranteeing its a B, even on the mesa site they say a main difference, is ALL A's have a built in cord..i was just throw off because between combos, heads (short long etc), A, B...the mark iv has alot of difference physical configurations