jack stand damage

[weej]

Hi everyone, I'm very, very new to car work, and I just jacked up my car for the first last Sunday to replace the engine mount. (It's a 2003 Boxster S.) Looking back at guides, it seems that it's pretty standard to place the jack stands under the factory jacking points, but I placed them under the...I think it's called a pinch weld? of the car.

For future reference, is that an unsafe place to put the stands?

Also, the weld seems to get crushed flat where the jack stands are placed. Do you think that area would be more susceptible to rust in the future?

Thanks for any input! I'm just attempting to slowly build up some knowledge about my car without destroying it or myself in the process...