Often, but not always! The imperative often has the same form as the second person present/future, but in the colloquial language people are far less likely to use the short-form present/future tense anyway, apart from some very common verbs.
In the Duo sentence above it shows dewch chi... - it is not usual for the chi/ti to be included in an imperative unless for emphasis.
If you are investing in any books on the Welsh language then 'Y Llyfr Berfau', a bilingual book by D. Geraint Lewis (usually about £9) is pretty much the standard reference list of the written forms of verbs, and it often shows the common, less formal forms where these differ. It has a few useful notes on usage, too. It does not try to cover the numerous dialect forms that exist for some common verbs, though.