Yes you won't have to worry about GMSTs as long as you didn't mess with any that you didn't intend to.
Unfortunately... without Bloodmoon you can't make the script I have work in your game. Bloodmoon adds a GetPCInJail function that this script depends on. The expansions are really fun, so I would get them. They add new scripting functions as well as content. GOTY version is dirt cheap. Used copies of the expansions could probably be found too. You're missing out on a lot by not having them, and for a game this old there isn't mush reason not to have it all. At the very least, the Morrowind Code Patch requires the game patched up to Bloodmoon, and you pretty much want that.
Here is the script anyway. I think checking for the skills after release is necessary either. Don't know what I was thinking. This will need to be started from dialogue, so the normal greeting for sending you to jail needs modified. In the result box for greeting 0, "Then you must serve a sentence of hard labor. Serve your time peaceably, and pay your debt to society.", replace GoToJail with StartScript, "jail".
begin jail ;You'll want to give it a unique name. Using your initials at the beginning is the standard. Avoid non-standard, non-alphabet characters. giro_jail, for example.short gotskillsfloat myacrobatics;Repeat for all skills. It would be a good idea to shorten the variable names, but leave the reconizable. myacr, for example.if ( MenuMode == 1 ) returnendifif ( gotskills == 0 ) set myacrobatics to Player->GetAcrobatics ;Repeat for all skills again. set gotskills to 1endifif ( gotskills == 1 ) GoToJailendifif ( gotskills == 1 ) if ( GetPCInJail == 1 ) return elseif ( GetPCInJail == 0 ) set got skills to 2 endifendifif ( got skills == 2 ) Player->SetAcrobatics, myacrobatics ;Repeat StopScript, "jail"endifend jail