no your vet will not routinely check for LP's and LS. Your puppy may check out just fine, yet without knowledge of his pedigree back several generations he may be a carrier of a wide variety of genetic problems. Without doing the proper background youre taking a chance of producing pups with genetic defects.
Also there are very few good breeders that will merely use an unproven stud accepting a puppy back as fee. Stud fees on an unproven stud are very minor at best.
these are good rules to live by -
WHEN SHOULD A MALE BE BRED?
1. When he is superior in conformation, temperament and health to most of the males in his breed. Whether this fact is established by showing him to his championship or by having him evaluated by others knowledgeable in the breed is of no consequence.
2. When he has passed all the health screenings for the bitch mentioned above.
3. When you've decided if you can live with a male who, once he's been used at stud, may suddenly forget his housebreaking lessons and start marking the sofa with urine.
4. When you are knowledgeable enough about pedigrees, conformation, health and temperament to know if the bitch being presented to him is a good match, or have a knowledgeable mentor who does.
5. When you have the fortitude and tact to turn down a bitch if you don't feel it would be a good breeding or if you don't feel she's of breeding quality.
http://www.canismajor.com/dog/reason10.html
this site may answer many of your questions when making the right decision using your kid for stud
good luck
Kimberly