Is it possible to unmap and recreate repeat's 'u' mapping later, for specific buffers?

[gfixler]

I'm having this issue with arpeggio.vim: https://github.com/kana/vim-arpeggio/issues/3

The following line maps 'u' and 't' separately to vim-arpeggio, and 'u' conflicts with vim-repeat:

Arpeggionnoremap ut etc...

I'm using the advice at the link to fix my own gk map for these buffers via ftplugin script:

unmap k
nnoremap <Plug>(arpeggio-default:k) gk

I don't know how to do this for the only other conflict, though, which is the 'u' key mapped by repeat.vim. I can fix it with a buffer-local unmap u in the filetype where I use this arpeggio, but I like repeatable undo. If I can't fix it, oh well, but I thought I'd ask.