So I have an old Shwinn World Sport that I'm upgrading since I got it for free from a family friend. One of the upgrades I'm doing is putting on brifters instead of the lever shifters on it now. The lever shifters are attached to the head tube right now and never had down tube shifters. I've attached an image of where my shifting cable runs on the downtime and wondered that since these are here do I need to install cable stops on the down tube. Let me know what you think, Thanks!

Your picture show cable stops on the down tube.

There are adjusters from Origin 8 and others that will fit into you current cable stops.

Thank you sir! I figured these would work since they looked like cable stops, but when I was reading other peoples' upgrades to brifters from downtube shifters most of them bought cable stops that went onto where their shifters were. Thanks again!

What you saw were cable stops/cable adjusters that bolted onto shifter bosses that were brazed onto the downtube to mount downtube shifters. Your bike apparently has stem shifters and those stops are only housing stops. You can mount brifters and use these housing stops but will have to provide an in-line cable adjuster for the front derailleur. Most rear derailleurs have an adjuster built in.

Not to burst your bubble but have you purchased the brifters, both derailleurs, cassette/freehweel, chain and perhaps the new wheel needed to make this conversion? You may be surprised at the cost.

Yeah I actually know the cost haha. I've been doing the research and planned on that whole conversion. Thanks for looking out for me though haha

I actually decided to go with Dura Ace 9-speed Index downtube shifters on the steel frame I'm building up, because I could get them brand new with cables for $67 (Chain Reaction Cycles), whereas the Brifters would have set me back around $200. I'm going with 9-speed rather than 10-speed because it gives me parts compatibility/exchangeability with my other modern-drivetrain bike.