yeah that is implied. I am showing you the node you use to concatenate the 000’s in the situation you need it for.
When to add the 000’s is up to you, but that’s just some simple check and if the check fails, then you add your 0’s.
So to summarize, the answer to your original question is “the variable which supports a number beginning with 0’s is a string”, but to build that string from some number you have to concatenate based on some ruleset you design.