'Top coats' on leather are pigments and clear coat finishes - 'Scotchgard' type products are topical protectors and these are not applied during the manufacturing process. Topical applied protectors do wear off with use and need to be reapplied, they are used to protect the finishes on leather from dirt and abrassion. You cannot tell if a pigment coated (finished, protected, coated - these are all names for them) leather has had a topical protector applied which is why it is important to do the job yourself . On a coated leather (as in most cars) a water droplet test would sit on the surface anyway due to the finish (it would only soak in on very old and cracked leather).
Test to see if a topical protector works are done on crust leathers (absorbent) to prove that the product works or not.
'Conditioners' cannot be absorbed by the leather through a pigment and clear coat finish so never get anywhere near the leather itself and as Lexol say stay on the surface and get sticky which only serves to attract more dirt. Once the pigment and/or clear coat finish has broken down and begun to crack this needs restoration work and if you add more 'conditioners' (which generally contain oils and waxes) at this stage they will only further weaken the finish and loosen the pigment. Moisture is the only 'conditioner' that leather needs and pigment coated leather needs to be kept clean to avoid break down of pigment due to abrassion and dirt (which acts like a fine sandpaper) and this is best done with products that have been tested on leather and will not in any way affect the finish on the leather.
Lexol products were produced for saddles and work in a different way to products designed for furnishing and auto leathers.
Hope this helps