Code Page 65001 handles Unicode features in NTU maps (NTU version includes Cyrillic ,Greek and non latin languages characters in labels search etc)
if you change it to 1252, you will loose unicode features, but map will work in your unit along NTU version addition files.
So you have to choose, because NT version doesn't provide some additions files for new units, because they don't exist in NT version that is for old units.(ASR2 for example)