Most of them of tantalum surface mount caps, but there are two axial electrolytics. It's actually harder to desolder the existing radial caps than it is to do the SMD caps, due to the extra heat required to desolder one of the legs from the ground plane.
Replacing the caps doesn't affect "authenticity." It's still a Mac SE/30, running on an 030 processor. Sure the caps I recommended aren't the "stock caps," but if the stock caps are dead and you cannot reliably boot, is there any merit to having the stock caps? Even a purist like me answers "no!" to that. In my vintage Mac enthusiast's mind, replacing the cheap stock caps with tantalums (which will last the life of the board, say 50 years?) will only increase the value of the machine. Why? Because the person who buys that Mac won't have to do the cap job themselves or pay anyone else to do it. It really is that simple. And so long as the machine EXTERNALLY looks stock, and so long as the motherboard is a real SE/30 edition board, it's still a "stock" machine, regardless of the caps having been replaced. Replacing the caps is as much as an improvement as when Apple removed the aluminum shield from atop the analog board of Mac 128k machines. Whether you have a Mac 128k with that piece of aluminum or not doesn't matter, nor does any EBAY auction talk about those things. Really, it's quite ridiculous to think excessively about whether replacing a capacitor is going to reduce the value of the machine. It's absurd.
But in all honesty you are thinking too much about making a buck on EBAY. Relax a bit, and enjoy the vintage Mac experience. Beside, if you don't do so, few people here will be eager to help you. Even I myself am not so enthusiastic knowing your intention is merely to sell a machine on EBAY. I'm am EBAY seller "skeptic" and "naysayer" far more than I am a "friend." But so long as you do so decently and sell for a respectable price to someone who will truly value the machine, I don't see a problem with your ultimate intention.
Anyway, if you have more questions about the $10 capacitor kit, just speak to Trag. He's very knowledgeable and can answer most any question you have about the caps.