in an attempt at a straight answer...

.... it depends.... I wouldn't assume that they should be played like they're dotted if not written that way. But then if it sounds good with it dotted then go for it. Contrary to the beliefs of many a folk muso, there is no right and wrong way to do things really.

If you are intending on playing it for people to actually morris dance to, try it both ways and watch the way they step to it - it will probably become obvious that with or without dots feel a more natural match for the dance. Or indeed a mixture of the two, with certain bars or notes played dotted and others not.

Finally, it may well be the case that the tune you want to play is commonly played in a particular way... (not that that makes other variations 'wrong'). Is there one specific tune we're talking about? If so, what is the name of the tune?

Jess