Another possibility is to have a machinist make a male mold in nylon or other plastic and lay-up the part in fiberglass (or, if you like sexy, carbon fiber, or kevlar). If I had to do this completely DIY, I might use the part to make a female two-part mold in fiberglass. Then use the mold to make duplicates in glass. In both cases, you're making a mold for a miniature boat hull and using that to lay up the glass.
I don't know if this is the best process for your application, but it does work for making one-off parts that are difficult to duplicate. Currently, I'm using this process to replicate the plastic hose barb on my headlight washer pump. The shape is vaguely similar to your part. I'm impregnating long fiberglass strands from some woven roving cloth and winding them around a length of polyethelene tubing, which is serving as the male mold. With this method you have to secure the ends of your woven roving with tape or weights to make sure it doesn't 'unwind' off the tube. Using epoxy thickeners or a compound like Marine Tech to impregnate the glass helps mitigate the inherent 'memory' of the fiberglass strands,
This link is to a company that does this kind of work, mostly on contract to the Navy. They also sell materials. I don't know if they'd undertake a small project, but the owner is a good guy and I do know he'd be happy to offer advice.
EDIT: The more I think about this, the more it seems that knocking out fifty of these is probably quite do-able. Maybe even better is that you could lay-up five at a time. Or whatever you might need to fill an order
For that purpose, I'd make both the inner 'male mould' and the outer 'female mould. I'd also integrate pins into the ends of one or the other mould to regulate the thickness of the lamination. I probably wouldn't try to mould the ring that protrudes from your part. I'd attach that separately. Your inner and outer moulds are, therefore, torpedo shape. That makes it relatively easy to lay-up the glass on the machinist made male mould, place the two part female mould around the male mould -- and then vacuum bag the whole affair to get even clamping pressure and a perfect finish.
If you want to get fancier, you can incorporate drains for resin overflow during the vacuum bagging. And there may be some way to integrate the ring-shaped protrusion. The guys at LBI would be better able to assess that.
Good Luck!
https://www.lbifiberglass.com/shop/