CS159 in dash tach retro fitting 66 cuda

IMG_4438.JPG Does anyone know if you buy the tach sold on eBay (I believe I bought mine from Van's LLC) do you need to modify to make sure the dash lights get into the tach for night time driving?

So I pulled my tach from the cluster to install the "modern" tach that will run on modern ignition in my 66' Barracuda.
It's made by Charger Specilities in NV.
One of the things I noticed is the lip around the tach face is about 1/4" tall. All the way around. The factory tach has the wall cut out on the top and bottom just like all the gauges. Just wondering if anyone else has had to "modify" so dash lights get inside.
Thanks,
Joe