If I put a meat thermometer in the oven will it correctly gauge the tempeture (if the oven isn't too hot?)?

I am trying to make some polymer clay kawaii charms. The sculpey clay baking instructions say I need to have the oven at exactly 275 degrees exactly. T he problem is my oven is old and doesn't have a thermometer any more. I have a thermometer that is called a meat thermometer. Its long and pokey with a gauge on the end. Will it measure the temp correctly if I place it on the oven rack? If not then how can I measure the temp on the oven.