Serial numbers can be found on the outside of the box that Pronto came in.
Some of the earliest packages were lacking although the most recent units we've shipped all have S/N's on the boxes.
If your unit was prior to the serialization marking, not to worry, you'll get software based on proof of purchase.
If Philips needs a list of purchasers from us, we'll be happy provide them with same, unless anyone can think of a good reason not to.
This will confirm purchase date and warranty status.