Why am I seeing different template options for different accounts?

I created a separate test account and had certain choices for templates, like Alameda.

I then went to my client's account and searched for that template to add, and it wasn't available. There was a whole different set of templates available, even though the menu categories all look the same in both accounts.

Any insight into this would be greatly appreciated. Thanks.

There are two different Squarespace versions 7.0 & 7.1
Seems like your client is using a different version.

More about these versions here: 
https://support.squarespace.com/hc/en-us/articles/360035290252-Squarespace-version-7-1-vs-version-7-0