They're just springs why waste your money on OEM when they're probably just generic springs anyway? I got Dura heavy duty from Amazon and they look identical to the springs my SMP came with. 4 pack for 10 bucks Canadian.
Heavy Duty Watch Band Pins (Spring Bars) for Traditional and Smart Watches | 1.8mm | Rust Resistance | Four Replacement Strap Pins by DURA Spring Bars
Heavy Duty Watch Band Pins (Spring Bars) for Traditional and Smart Watches | 1.8mm | Rust Resistance | Four Replacement Strap Pins by DURA Spring Bars(20mm) : Amazon.ca: Clothing, Shoes & Accessories
People can use whatever they like, but I replace a ton of spring bars (I replace them on every watch I service) and I can tell you that the type of generic spring bar you have bought and linked to are no where near the quality of Omega bars. Since this topic comes up every so often, and there's usually someone stating what you are, I took this comparison photo a few years ago to show the difference:
The Bottom bar is a Swiss made 1.8 mm diameter spring bar, made by Horotec. The top one is an Omega 2207 spring bar, for 20 mm lug width and bracelets.
The difference in quality should be apparent, but if it's not take a look at how the tips of each end of the spring bar are contained. The cheaper spring bars have a simple crimp at the end, but this doesn't keep the tips from being able to flex - you can see one is tipped up and one is tipped down. This movement creates movement in the end link, and over time the tip moving around can cause that crimp to open up. I remove bracelets pretty frequently that as soon as the end link is pulled away from the watch, the tip of the spring bar falls out of the bar.
The way the Omega bars are made, this tipping doesn't happen and the bars are of much better quality. In addition, the Omega bars are made for the hole in the lug, where some generic bars are too small, and this can lead again to movement and wear, like this:
Omega bars are more expensive, but personally I don't want to be cheap on the only part that keeps a multi thousands of dollars watch from hitting the ground. For me it's a couple of extra bucks well spent.
For the OP - you can contact the Omega service center nearest to you to get spring bars directly from Omega. These are not restricted parts so they will sell them to you directly.
Cheers, Al