Steps to display the 512-character font in WordPerfect 5.1:
Shift-F1
2 - Display
(At this point make sure that 3 - Text Screen Type says "Auto Selected"; if it doesn't, use 3 - Text Screen Type, then 2 - Auto-select.)
after pressing 2 - Display, then
1 - Colors/Fonts/Attributes
then, you should see a menu of five choices; choose
5 - 512 Characters...
then F7 until you're back at the editing screen
If you don't see a menu of five choices, with one of them as 512 characters, then go back to 3 - Text Screen Type, choose IBM VGA (& Compatibles), then highlight 80x25 16 Color, and choose 1 - Select. At this point you should be able to select the 512-character font.
Now you can open charmap.tst (Shift-F10, charmap.tst - or F5 and select the file) and see the extended characters.
I've spelled out the instructions in excessive detail in the hope of preventing frustration on anyone's part!
On my Windows XP system, I use an Nvidia GeForce 7600 card (because the 7600 series was the last one to provide a continuous underline in mode 7, which is NOT relevant here, of course). When I run WP in full-screen mode, the second font bank is displayed in normal intensity, not bold. I used Tseng 3000 and 4000 cards for many years before I switched to Nvidia, and they also displayed the second font bank in normal intensity. So did my original IBM VGA card, from 1990. Also, the video hardware in all the ThinkPads I've ever tried also do this correctly - but my newest ThinkPad is admittedly a few years old.
Are you saying that some cards display the second font bank in bold intensity? I guess I wouldn't be surprised if the most modern cards don't even try to handle this feature. I've noticed that some new cards don't even support the underline attribute in mode 7....
PS: Most of what I know about text mode in WordPerfect is here, but not much of it is relevant to this question:
http://www.columbia.edu/~em36/wpdos/textmode.html