Look under the keyboards, on the left side looking up from the pedals
and you will find your model number. You might need a flashlight.
Organs by Model Number
PDI®
Trillium™
Insignia™
Allegiant™
730
735
751
790
795
785
805
835
885
905
940
945
950
955
960
T787
T797
T807
T837
T927
T957
T967
i557
i577
i537
657
677