Hi @jms211
I would say that the answer is no.
This is based on that the screens have different part numbers (at least according to ifixit) i.e. the part numbers for the Series 5 44mm screens are IF450-000-1(Ion-X glass) & IF450-000-2 (Sapphire Crystal glass) and the Series 6 is IF441-000-4.
They wouldn't use different part numbers for each watch screen if it was compatible for two different series watches.