order up! Pretty sure this is what you're after! Happy to help.

once you've enrolled this computer & jamf has all the proper information (ie, the name you want & the asset tag), run this script.

https://github.com/Hugonauts/shellscripts/blob/master/JAMF%20API%20-%20Set%20Custom%20Login%20Message

#!/bin/bash

## Enter the API Username, API Password and JSS URL here
apiuser="apiuser"
apipass="apiuser"
jssURL="https://my.jss.company.com:8443"

## Get the Mac's UUID string
UUID=$(ioreg -rd1 -c IOPlatformExpertDevice | awk -F'"' '/IOPlatformUUID/{print $4}')

## Pull the Asset Tag by accessing the computer records "general" subsection
Asset_Tag=$(curl -H "Accept: text/xml" -sfku "${apiuser}:${apipass}" "${jssURL}/JSSResource/computers/udid/${UUID}/subset/general" | xmllint --format - 2>/dev/null | awk -F'>|<' '/<asset_tag>/{print $3}')

## Get Computers Name
Name=$(networksetup -getcomputername)

## Edit the raw text between the quotes below, do not edit ${Name} or ${Asset_Tag}.
loginWindowMessage="This Bob's School Mac is Named ${Name}, has Asset Number ${Asset_Tag}, and is assigned to Bob John's 3rd Grade Class. If found, please contact Bob's School at xxx-xxx-xxxx."

/usr/bin/defaults write /Library/Preferences/com.apple.loginwindow.plist LoginwindowText -string "$loginWindowMessage"

This was my first Request on JN. I am always hesitant to ask, because I don't want others to do my heavy lifting, but I find the sheer volume of information to weed through to be overwhelming, and I rarely find examples/answers that even come close to solve my issues. Plus, I'm new to a lot of this, so I'm doing my best, but I just run out of time and am exhausted from search after search.

Anyway, you're script worked EXACTLY how I wanted. Amazing, elegant and just so kind.

Thank you so very much.

Happy to help, You're welcome. Never hesitate to ask, this is what we're here for & this is an incredible community, you can learn a lot here. We've all started somewhere & I for sure know what its like to be in your shoes. A lot of people here are eager to help.