It may be but not clear from the title. Even you said you need a fortune teller. From a risk management perspective if you can't tell if you got a good one then DIY is an acceptable risk to compare with more expensive pre-made batteries for some people.
For a product to be sold it will be sold on uniqueness, price, or quality, or a combination of the three.
I believe that most of these batteries are built to a price not a standard, so it's a flip of a coin if you get a good one.
The worst culprits for reducing quality in the name of costs are the established companies.
Snap-On for example. Once synonymous with the best quality made in the USA tools; now: View attachment 45816
And the very worst offender in my opinion is Aston Martin.
An iconic British sports car now reduced to simply relying on the name to make sales:
Yes, this is an Aston Martin. View attachment 45817
Sorry for the rant.
Digression here, but Aston Martin had a good reason for rebadging this Toyota in an attempt to up their average fuel economy which is most likely in the teens. It's too bad they didn't simply electrify one of their supercars but the legacy of their big V8s would be a hard sell to traditionalists. As if the Cygnet wasn't, with a total run of about 300.