Colombia - 50 Pesos 1980 - varieties or printing error?

I have two Colombia 50 Pesos Oro, dated 1 January 1980, both of them appear to be legit and neither has the name of the printer.

ref. P#422 - https://en.numista.com/catalogue/note213801.html.

On one of them you can see large numbers 50 (over the watermark and next to the right shoulder of the portrait), similar to those visible in the mid-1980s notes printed by Imprenta de Billetes - Bogota,  ref P#425 

N#213919

but, they cannot be seen on the other note, which appears to be the case for those printed in the mid-1970s by Thomas de la Rue - London, ref. P#414

N#211665

Other than the missing numbers 50, I do not notice any other difference between the two 1980 notes.

Are there known varieties or printers for the 1980 - 1983 series of the 50 Peso notes?

Could the missing numbers 50 be indication of printing error or counterfit?

The second and third links are not working (I think). I do not have an answer for you. I was just busybody here, aka, learning myself.

you'll have to delete the ‘);’ in the address bar

Is this the one you are looking for?

here are the two notes in question

In my opinion, what you have are just two difference varieties. To me, the give away are the two serial numbers.