Anyone ever see these "bumps"?

Hi All,
I'm working on a 67 vert I've garaged for 20 years so its in really good shape. Just recently flipped her over on the rotisserie and noticed these "bumps" all over the floorpan reinforcement. they're on both passenger and drivers side. I never really noticed them before now since I was always on my back under the car paying attention to other things. I'm pretty certain these are original panels, anyone have any ideas? Maybe it was just some assembly worker who was bored?

Of course, this is the first time I'm trying to post a picture, so bear with me if I mess it up

bnickel said:

those are just paint bubbles or droplets from the last time the car had the underside painted. the original color of the floors would have been red-oxide primer not black so that's not original but the panels do look to be original.

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Interesting. It's hard to tell exactly what color they may have painted it since there's such a thick layer of crud and oil down there. As I remember back when it was on the road, the engine threw oil out the right side pretty bad. No complaints tho, the layer of oil kept a lot of rust from happening on the underside.

On a related note, I was planning to learn how to soda blast. Looking at getting this tool: http://www.eastwoodco.com/shopping/...temID=16321&itemType=PRODUCT&iProductID=16321

It looks like low capacity, but of course this project will happen in stages anyway. Anyone have experience with this product and do you think it will work on the undercarriage? I'm pretty sure it will work fine on the body panels themselves.