The '54 bumper guard part nos are not interchangeable with '52 part nos.
The '52 pictured has the optional Deluxe front inner bumper guards (pt nos 1345914 right, 1345915 left). These were standard on the '52 Roadmaster and fit other '51-52 Buicks.
The standard guard for the '52 Special/Super cars and all '51 series is thinner and does not come down over the front of the bumper face bar. These are nos 1343286 right, 1343287 left.
This will give some idea of which cars to look for. Sometimes the part numbers will come up on eBay for NOS parts.