Does it really matter as you have no Paypal protection with regular small parcels, red and express satchels anyway unless you pay for SOD.   Why not use click & send then you know exactly where you are?

Regular small parcels have the postcode on the receipt (when the proper button is used by AP staff) which is all you need for proof of posting and a stat dec confirms the address to which the item was sent.

I have used regular receipts to prove postage before PJ.

They have the buyers postcode and the date the item was sent which are minimum requirements for paypal seller protection policy coverage