Using Allegro's definitions; there shouldn't be extra components, but there may be extra symbols.
To find extra symbols:
Zoom out so you can see the whole board then turn on pins for all layers. Using the highlight (assign color) command with the find filter set only to "Symbols", window around the board to highlight all symbols(with pins) in the design. Then using the dehighlight command with the find filter set only to "Comps", window around the board to dehilight all components in the design. The remaining highlighted symbols aren't in the schematic (although they could be symbols you want to keep like tooling holes, fiducials, etc.).
Hope this helps.
Good Day, R².