That's a great question!
My take on it would be this...
We know that the discernable level of peat in any whisky becomes less as the whisky gets older.
In other words, a cask of a 15yo whisky will seem slightly less peaty than that same
cask would have when it was only 10 years old.
We can therefore extrapolate that the discernable levels of peat we taste in our drams will seemingly diminish with maturation
Now...maturation, of course, is a function of the cask. Some casks (2nd or 3rd re-fills) will mature whisky much slower than a first-fill cask.
So to answer your question....if the OB contains a vatting of 10 year old casks, of which most are 2nd fill, and then an IB releases a single cask that was actually a first fill, then yes
, the IB will seem peatier than the OB, even though they were distilled at the same time and perhaps even on the same distillation run!
The first fill will have matured the whisky much faster.