My Omega DII predates grounded outlets by several decades.

There are really two issues with respect to enlarger grounding.  An
enlarger with a three-prong plug (and with three-conductor wire) will
provide safety grounding for the electrical circuit, and is certainly
desirable.  But the second issue is that grounding the enlarger frame will
make it easier to control dust.  What I have always done (I'm in my third
darkroom at this point) is to provide a grounding lug on the wall behind
the enlarger, and make a connection from that lug to a convenient point on
the metal frame.   Grounding the frame actually enhances safety as well
since the electrical components should be contained within the grounded
metal housing of the enlarger head.

The easiest way to set up a grounding lug is to tap into the (bare, or
uninsulated) ground wire in a receptacle circuit.  If the wiring in your
room does not include a bare ground wire, an alternative is to install a
wire clamp on a copper water pipe, and then wire from the clamp to the
ground lug.  The clamp should be on a cold water pipe to assure that it is
not isolated by a water heater.

Not only should the outlet be grounded, it should have a GFI (ground fault
interrupter) circuit. This is required by code in all new bathrooms, etc.

From a safety viewpoint a ground-fault interrupter is mandatory.  All
outlets in a room with a water supply should have GFI's installed:
bathroom; kitchen; laundry room; outdoor outlets; garage ....

When you install GFI outlets they will be three-prong.  If you don't
have a ground in your house wiring then have one installed for the
above mentioned rooms (at the least).

If the enlarger does not have a 3 prong cord then you should install
one.  Connect the ground wire to metal where the cord makes ingress:
lamp housing; frame; motor box; or baseboard.  Make sure all metal
parts of the enlarger are grounded, check with an ohmmeter from the
ground lug of the power cord to _all_ exposed metal parts (within
reason - lensboards, aperture rings and the like can be ignored).

Everybody who ever died of electrocution made the same claim.