both at once?

[dwest]

My 89 300 CE is leaking from the front crank seal. I'm taking it in to be fixed. My rule is I don't DIY jobs that require an expensive tool I'll use only once.
Does it make sense to have him replace the upper timing chain cover "U" gasket while he's in there? It's not leaking, but from searching this site I know it will, eventually. Additional cost about $100.