Scrum-half Lawson is one of 10 Scotland internationals in Hadden's starting XV that meets the Eagles on Wednesday evening at Henley.
Having featured in each of Scotland's last six matches, the 26-year-old would appear to be well placed, but he is conscious of the fact that Mike Blair is expected to recover from the shoulder injury which has kept him out since January by the start of the World Cup.
"Mike Blair and Chris Cusiter are both very, very good players, and they are very experienced campaigners now, and it would be naÃ¯ve of me to think that the amount of experience they have built up over the last couple of years isn't going to come into play - but I've got to try and wipe that advantage out and gain in other factors," said Lawson.
"It is heartening to hear Frank say that the likelihood is that he'll take three scrum-halves, but at the same time you want to be first pick and not sneaking in as third choice.
"Going to the World Cup in any capacity is a great honour and privilege, but at the same time you want to be the guy who is playing."