Yes. If you want a cesium calibration source, you can order one online from United Nuclear.[1] Costs $145, plus $15 shipping. Anyone can order. "If you're ordering hazardous items, don't forget to sign the disclaimer on the bottom of the order form!"

Plutonium alpha sources are available from Eckert and Ziegler, and can be ordered in the US from Direct Scientific.[2] Call for pricing. They're a disk with some plutonium electroplated onto platinum on stainless steel. There's no window, because this is an alpha emitter and the particles would not get through.

As hazardous objects, these rank well below a steak knife.

[1] https://unitednuclear.com/index.php?main_page=product_info&c... [2] https://www.drct.com/dss/sources/alpha.htm

This particular case isn't terrible, but it illustrates the general attitude towards material security that could be seriously bad. With materials like this I don't think there is an acceptable threshold under which we can say 'no big deal' if lost.