I have two buddies with 1520s, identical except I think a year apart. We can fit 9' fly rods in one, but not the other (horizontal, with the rod tubes into the front bulkhead).
I'd check the tubes and what's behind them. I think there is foam that prevents the rod tube from going further forward, but can't remember exactly. So, it's definitely possible with that hull, I just can't remember exactly what prevents it in some of them.
@Lmhanagr should be able to help out if he sees this, but he's not on the forum very often. I'll see him tomorrow and/or Sunday, so I'll try to remember to ask.