X290 Peugeot Boxer rear dampers query

Our late 2014 X290 Elddis Majestic 195 was recently M.O.T.'d & an advisory given for a slightly misting n/s/r/ damper, no problem we thought, we'll source new o.e.m. dampers & have them fitted,

It transpires that for some reason the previous owner has replaced the o.e.m. dampers for longer versions prior to our ownership which commenced with the vehicle having just 8383 recorded miles at 2.5 years old.

Given that o.e.m. spec' dampers are readily available we wonder why this change was made ?

The quandry we now have, is that should we replace these non o.e.m. dampers with o.e.m. spec' ones or attempt to source replacements identical to those currently fitted ?

If anyone can offer answers to these two questions we'd be grateful.

Thank you.