Tune-O-Matic Style Bridge Question

[2-5Guy]

I have noticed that two (or more) guitars which are identical in brand and model that have TOM bridges and identical string heights can have their bridge heights vary in relation to the body. Why is that? Is it because set necks can vary in angle in relation to the body depending on how the builder attached it?

[JohanAbrandt]

I have noticed that two (or more) guitars which are identical in brand and model that have TOM bridges and identical string heights can have their bridge heights vary in relation to the body. Why is that? Is it because set necks can vary in angle in relation to the body depending on how the builder attached it?

Yes

[JCat]

In addition to neck set angle, there's also variation in the height of the fretboard (including fret height) as well as variation in the height/arch of the top. And there's variation in the height of the saddles and depth of string slots as well as the height of the bridge body (there are 3rd party replacement bridges with slightly different specs).

But the single factor having most impact on bridge height is the setting of the truss rod and the resulting neck relief that affects effective neck angle. When tightening the truss rod the bridge has to be raised to maintain string height across the board.
You see that it's a matter of where string height is measured (we often use the 12th fret for reference, even though it actually don't tell the whole story). A guitar having severe forward bow would have the bridge screwed all the way down and still got plenty of string height at the 12th fret.