How difficult to fit barrels?

[tom tutwiler]

I'm sure I'm asking a question that has been asked constant times, but I'm getting old and forgetful so I'll ask once more.

How difficult is it to fit a set of 12 gauge number 2 frame barrels to another 12 gauge number 2 frame gun? Both guns are extractors. Also, does it make a difference between early (say 1900 made VH) versus (say 1910 made VH)?

Lastly, if one makes the switch, is is better to have the replacement barrels available with their matching forend, or using the existing forend on the original gun?

Inquiring minds want to know. PS. Assume the same rules would apply with a 16 gauge or a 20 gauge etc., as long as the frames are the same size.

Thanks for educating me.