good that you are sympathetic to it, but the tach and speedo are not that hard and should come off with a little patience. Suggest first bounding the bezel in a hose clamp (put a big ring around the circumference) to simply keep the whole thing from distorting as you start to work the area at the tab; but the ring tabs will bend up, this is the way they come off (completely different from the 50mm gauges). Be very patient, slowly work the thing up (don't try to start from one and and have it unpeeled at the other...massage the thing up).
Assembly is the reverse of disassembly, but clamp the gauge face down on the edge of a table before bending the tabs in (make sure the fiat is snug before closing up).
Cutting off the tabs is not a good idea, neither is gluing the bezels in place. As you tighten down the clamps holding the gauge in the dash, the pressure of the dash will tend to push the bezel OFF if you don't have that tab. You need to have the roll on the back of the gauge to be able to keep both gauge and bezel in one piece. You should not glue, esp. for the speedo (which some day may need calibration or repair).
And no, as I can tell replacement bezels for the speedo and tach are not available except off Pantera and some Alfa Giulia. The size is just smaller than British 5" bezels. The 2" bezels and cut glass are easier to find (Auto Electrical Spares) but they are 1 mm thicker than the Veglia trim...).
(Otherwise, as well pass on the Fiat 850/124 bezel sets in Chrome...They are made of steel, not more pliable brass, they are impossible to bend back down. unless you put the instrument in a lathe, as Veglia did. Also, the Fiat 850 tach/speed is too small for the Goose/Pantera (even though the guts are the same). The Auto Electrical Spares 2" replacements at least provide tabs so you don't have to work the whole ring when putting back on. (btw, the Fiat 124 rings seem unworkable, when gauge bodies went to plastic the bezels went to aluminum (think aluminum foil) and they are just impossible to reuse). After mangling the first few bezels I took off the Goose, I ended up with more patience and recovered good bezels off early steel cased Fiats).
I've seen some guys advertising that they can make a bezel--I suppose its a process of metal spinning...It would be a nice thing for someone to spin a few samples for the DeTomaso community, (or even cut the 3.0mm x 110mm glass) but realistically the DeT gauges are easy enough to find and rob parts if worst comes to worst...Lee
https://joellevinecompany.com/Dial-Bezel-Making
