IMO it is worth marking something, as a general warning to cyclists etc that they might need to slow down, plus it may be a useful feature for navigation.
Simplest would be just to add barrier=gate tag, plus the appropriate access tags, ie foot=yes, bicycle=yes, horse=yes, motorcar=no, motorcycle=no
Then its clear who is able/allowed to pass through it.
Or if you wanted to map each barrier, you could split the way into several adjacent ways at that point, with a different barrier on each.
There’s a few tracks around here that have (usually locked) gates on them, with kissing gates alongside. I’ve just mapped them as barrier=gate, plus the access tags.
There’s also some cattle grids with a track and a gate alongside for animals etc, I think they would be worth mapping separately, though I’ve not done any yet.
I agree with Vclaw. Where I’ve come across 2 gates next to each other I also usually tag a single node as barrier=gate and then put various access tags.