I apologize. I almost forgot for a moment which subreddit I'm on. After all, I'm in r/MechanicalKeyboards, where having a genuine opinion that differs from the majority of people is equivalent to being pedantic. Thank you once again for the reminder. I truly appreciate it.

I would also like to point out that I believe you're right in your assessment with the arrow cluster. This might be a variant of the standard 1800 layout, but not actually the 1800 layout. I think it's a cool layout though.

I'm not sure when definitions changed for the numeric keypad, but it's always be 17 keys where I grew up, plus minus a couple of keys.

I'm not sure where you got your definition of numpad, but numpads contain four columns with the mathematical operations you mentioned.

I don't think this is an 1800. 1800s generally have a numpad on the right, but this doesn't.