I do believe tour TT is worth more than the typical model however I doubt you will recoup your total extra cost.
Your unit is only worth what someone else is willing to spend. There wasn't a large demand for this feature when you bought it and I imagine demand won't be very high now.
To the right person the storage and axles will be very valuable but finding that right buyer will be tough.
I had a custom generator platform installed on my last rig. The entire setup was great nevertheless I did not recoup my cost at resale time and I did not expect to.
You will have to negotiate the price just like any other rig, keep in mind one of a kind customizations generally do not add significant valuer
19'Duramax w/hips, 2022 Alliance Paradigm 390MP >BD3,r,22" Blackstone
r,RV760 w/BC20,Glow Steps, Enduraplas25,Pedego
BakFlip,RVLock,Prog.50A surge ,Hughes autoformer
Porta Bote 8.0 Nissan, Sailun S637