Reed strengths are guidelines within one maker. One makers medium is another makers hard or soft.
So even if the Lesher Artist specified that they were "medium" they could be extremely soft, extremely hard, or just right depending on where you're coming from.
If the reed is too hard or soft for you I would suggest you play with it for a few days to see if you can get used to it. Especially if you're going to be stuck with the one strength they're offering. Otherwise you'll be hand adjusting yourself and could quite possibly ruin the reed in the process.
These are a couple of inexpensive handmade reeds as an alternative though:
http://www.nielsen-woodwinds.com/pc-5039-133-oboe-reeds-purple.aspx
http://www.nielsen-woodwinds.com/pc-5038-133-oboe-reeds-green.aspx
I'm partial to purple, but I've bumped into someone loved the green more than purple. Try a few of both maybe you'll like one over the other. Each color signifies a different maker.
There are so many other makers out there though that make wonderful reeds. Give others a try too, these are just the cheapest decent reeds I've come across.