I have 3 sets of bars.
1 is from an 84 Californian, the second is from an 84 Blue Max and the third is off an 87 Expert.
They range in sized from about 24.5 to 26.5 inches long and 7 to 8+ inch rise. None of them appear to have been cut.
Two of them look like they were welded by a blind man. Only the 87 Expert bars has decent welds.
If I didn't pull these off the bikes myself I'd swear at least 2 of them were knockoffs. My question is... Are these bars all over the place in terms of size and quality? Thanks.

mongoose always had good welds. That is about what i know about them

is the up sweep and back sweep the same ?
how about the knurl

There is a mongoose ad in one of my magazines that shows a line up of the bars and there are like 7 sizes all with .5" increnments, as far as the welds go I think they also show that they had a Hi-ten steel line, and those were probably on the lower end bikes.

Yes they are Pro Class bars

I had a few NOS Mongoose SS Bars my self

I remember 'Goose bars always having a sort of high crossbar, but Schwinn also had a very similar bar from what I remember.

Unfortunately, no they are not Pro Class Bars. They are Team Cycle brand. In 84 when the market was booming Team Cycle sold lesser quality copies of higer end components in Department Stores. When you mentioned the weld on those bars the first thing I thought of was Team Cycle.
Photos taken from BMX Action, May 1984, page 85. The advertisements in those old magazines really help clear up a lot of the questions that people have.
Note that in the specs they describe them as "For Street Use Only"

Team Cycle, didnt have a manufacturing facility, they bought them spec'd just like many of the manufactures did, unless you are pulling them out of the bag or off a bike pulled from a box, there is no way to tell what a cheap bar is other than a cheap bar. Schwinn mongoose and khs and kent and cycle pro and a few others all had bars that looked pretty much the same from 85-89

The Mongoose bars GBOSS has pictured are from 1st gens.

The bars in question by Pauly are 2nd gens.

When Mongoose went forward in the time line the 1st gen was manufactored here.
The second gen stuff had the lower end modles made in Taiwan.

Couldn't that explain the difference in welds ?

You would need all bars in question side by side to really see what the deal is.

Add Team Cycle into the mix and it's an endless answer of speculation ...

Rob