Replacing Header Wood on a 31 Murry Sedan

[California Charlie]

I'm preparing to replace the wooden header in a 1931 Murry 4 Door Slant Window Sedan and have a question about doing that.

I've heard there may be some upper sheet metal cutting to remove the old wooden header, and rewelding the metal cutting after the new header is installed.

Has anyone heard about this, (is cutting and welding necessary) and if you were involved with ever replacing a wooden header on a 31 Slant Window are there any pointers you can provided to me.

also:

Recommendations for the best Model A Ford replacement top wood Company.

Thanks in advance to anyone who helps me with this question.