The Middle Series
This is the second of three major categories for late sixties Les Pauls. As we progress through these three sections, the construction of the guitars will get further and further away from the 1950's style (and will decrease in value). It is important to remember to make up ones own mind about the merits or pitfalls of these changes. A guitar from any one of these sections could easily be perfect for you. Also, unofficial production numbers from this era indicate that production increases as we progress. This implies that each succeeding era becomes more common.
The Middle Series are great compromises between price and construction. They are increasingly collectable and have always been undeniably playable. Their bodies are exclusively early 69 design, 1-pc construction. The necks are 3-pc construction throughout. Although they lack long tenon construction, the Standards gain "Mini-Humbuckers" early in the run. These pickups are well regarded by players. One source informed me that their 845xxx GT cost them $348 back in 1969. This is the era that Gibson chose to base their "1969 Les Paul Deluxe" reissues on. They are covered in the "Current Reissues" section. Note the reissues aren't very accurate for whatever that's worth. :)
Think of 'The Who', and you'll think of the Deluxe sound.
Concerning Standard models only, Mini-Humbucker pickups enter early in the run. They have cream rings and have typical late 60's "Patent Stickers" on their bottoms. The rumour is that these were initially leftover Epiphone parts, but I don't know if there is anyway to prove that one way or the other.
Honduran Mahogany as stated in the flyer released in 1968. Maple top. Three-piece mahogany neck (with two little seperate wings to form the holly shaped headstock) throughout this category. Although it is unclear when the center seamed maple top disappears in the category, it is certain that it does. Let it be noted that many, if not nearly all 50's Goldtops had non-center seamed tops. The very first parts of the run have the early 1969 style bodies. This includes the route for receiving a long tenon. This is most certainly exhibited on the last of the 5xx,xxx series (565xxx & the rare 600xxx). Eventually, the route was modified to barely extend into the pickup cavity. (AKA, not under the pickup's center like before.) This shorter route probably comes into the neck cavity by about a quarter inch whereas the long tenon route was about 3/4 of an inch. Although the tenon route is changed, the remaining features are identical to early 69 bodies. In essence, they are still pre-genuine-pancake bodies.
These guitars exclusively have a transitional tenon neck joint. These are flat bottomed like long tenons, just not as long. NOTE: A very small number of Middle Series guitars shipped with a long tenon body and a transitional tenon neck. This occurred ONLY in the 565xxx and the rare 600xxx serial range. Although absent on LP Customs (for obvious reasons), LP Deluxes have a block of wood crudely glued in to fill this gap. The block allows the mounting bar for the mini-humbuckers to be installed. Be careful to make sure what you are buying. This block is occasionally glued in with care and can appear to be a long tenon.
Note about this image: This is a photoshop hack job of an Historic Series Gibson that was cut in half. It is just for educational purposes and not precisely similar to the actual neck joints. Thanks.