ot: copy physical mail files ?

dumb question warning:

I have two email accounts, me@tld1 and me@tld2 often, get emails intended (by me) for me@tld2 sent to me@tld1

this is purely for my own preferred record keeping preference,

as I run the server, is it 'a really bad things' if I simply copy relevant mail files from /var/vmail/vmail1/tld1..../cur to /var/vmail/vmail1/tld2.../cur ?

rather than forward emails as I have been doing?

thanks