retrieving filed value via its label

I am creating a function using the "gform_paypal_fulfillment" filter.

I got a little stuck, because I am trying to get a specific field value. $entry does not work for me, because I have several form tht need to use that function and in each form the filed ID is different. So Ican't use $entry['3'] because on another form it might be $entry['5'].

Is it possible to retreive the value of a field through its label rather than the field_id?

Thanks