was kamen rider x the only showa rider who had a personal weapon?
By personal weapon, I assume you mean the Ridol.
It is a pretty iconic piece of tech for the X Rider and very, very versatile. However, it is not the only personal weapon used by any Showa Rider. If you go back a series, there is a Rider who has a very versatile weapon:
Unlike most of the other Riders before and since, Riderman was not entirely cybernetic, only his right arm was. He was originally remodeled by Destron to fight Kamen Rider V3. However, he switched sides and was eventually given the title and position of the 4th Kamen Rider.
His right arm comes with many interchangeable attachments including:
The Power Arm
The bladed arm was good in combat but also useful to slicing through barrier such as walls and locked doors. It is by far his strongest arm attachment.
The Rope Arm
This arm ended in a grappling hook attached to a long coil of rope that was wound inside the arm itself. This was used for climbing, escaping and even grabbing a foe at a distance to bring them in. A related variant was a net arm that could, as the name implies, fire a net to hold opponents.
The Drill Arm
Hey, sometimes you just need a drill. When the Power Arm won’t cut it (no pun intended) the Drill Arm was there for some serious penetrating power. Not as directly useful in combat but still fearsome, this arm was more tool than weapon.
Now, further down the timeline, we come to a Rider with a very similar weapon to Kamen Rider X, though perhaps not as multi-functional and that was 1988′s Kamen Rider Black RX and his Revolcane.
Like the Ridol before it, this weapon comes out of RX’s belt. It is used as a blunt weapon but can also be charged to function as an energy sword to dispatch enemies.
His other two forms also come with personal weapons beginning with Roborider and his Vortech Shooter:
This is an energy weapon befitting the futuristic, mechanized form of its user.
There was also his Biorider form and it came equipped with the Bio Blade sword:
So there you have it. There are at least two more Showa riders with personal weapons.