Since it doesn’t state butted or not, odds are it’s not, correct?

This is your High Plains? The Schwinn catalogs for '90 and '91 both say 4130 Cr-Mo; the marketing blurb on the '91 says "double-butted."

yah. It’s the high plains. The number on the plate is 3619, so I’m feeling safe to assume it’s a 1990.

The frame is the magic. Get yourself some higher end components and ride like Clint!

I might need to find a drifter sticker for it.

I bought the thing to sell, but I’ve been riding it around and I’m really digging the easy going comfy feel.

My Trek 990 has oversized DB OXII heat treated steel, so it’s quite light, but the road vibrations are not as supple feeling as this old 4130.

I have the cockpit parts ready to do a quick and easy drop bar conversion. I guess if I can get the bike into the garage without the girlfriend noticing, I might be in luck. I have an 86 Chrome diamondback MTB that might be ready for a tuneup and a flip. We shall see which one I like more.

The marketing department normally wouldn't miss the opportunity to proclaim a selling featue like "butted" tubing. Consequently, it's likely plain gauge. Most manufacturers (Tange being the major exception) used single butted seat tubes, in which case it's often possible to determine if the tubing is plain plain or butted based on the tubing wall thickness, which can be calculated from the seat post diameter and seat tube diameter. If I recall correctly, True Temper favoured single butted seat tubes.