Freshbook Ids and leading zeros

[max.b...@callawaycloudconsulting.com]

Hey, wondering about the structure of FB Ids.

We have an Salesforce Sync that gets updates from Freshbooks via SOAP. In particular, when getting invoices, we receive the object_id with leading zeros 00000813942. However, in our callback, say when an invoice is deleted from FB, FB sends the object Id without leading zeros, like 813942.

Not a big deal managing them this way but I'm worried about integrations breaking down the road. 

Can any of you shed any light on the structure of these Ids? Will they always be 11 characters long when leading zeros are provided? Any reference documentation I missed?

Thanks!
Max