For the meaning of the phrase, you nailed it.
For the pronunciation, I'll tackle the question from another angle.
得 has 3 pronounciations (de2, dei3 and de).
It is only pronounced děi (dei3) synonym to "應該"， it means "should/have to/must to/need to/supposed to", e.g.: 我得走了。(I gotta go) In your question, a minor correction, it should be either 得(字)的发音 (得's pronounciation) or 得(字)得怎么发音 / how is 得 supposed to be pronunced? The literal translation of "得" 得怎么发音 (de2 dei3 zen3 me fa1 yin1) is close to how _must_ it be pronounced?
Otherwise, it is pronounced dé (de2) in most cases, when it means to "obtain/possess/have" e.g.: 得獎 (win a prize)，獲得 (obtain)
得 is prounced de when it functions as a particle / 助詞, e.g.: 跑得快 (runs fast) (For the reason, I assumed it'd be really weird to pronounce it as de2, you could try them both and compare yourself.)
Hope this clarifies it for you. Good luck!
P.S.: You might find this useful,
A simple way to distinguish 的地得 for their most confusing usage,
的 - possesive
地 - adverb
得 - particle
I'd say don't fret over whether to pronounce de2 or de, it's less a sin than saying de2 when you mean dei3. It's a personal pet peeve for people who make that mistake, and trust me, tons of Chinese don't know it is supposed to be pronounced as dei3, including probably more than half of my family. However, exercises on the pronunciations of heteronyms are overly practiced throughout elementary school and even repeated in early junior high. Thus, it helps to ensure the students of our/my generation not to mispronounce. I think before my time, being a Chinese teacher doesn't often have to take certain teacher's evaluation exams and Chinese exams. The qualification was much lower 2, 3 decades ago. On top of that, China has many different regions with people pronouncing things all differently. Hence, the formation of accents and dialect. So you'll likely to meet a lot of Chinese who stumble over pronunciations.
Another note on 去聲／light or 陽平／ 2nd tone, Taiwanese tend to pronounce a bit differently than a mainlander. They sometimes pronounce 陽平 when mainlanders pronounce 去聲. Another thing is they like to emphasize with 有, i.e.: 寫作業了嗎？(Did you do your homework) They say, 我有寫啊(I DID do it) instead of 我寫了(I did it/I have done it)。Nowadays, it's not uncommon for mainlanders to emphasize with 有, probably because of the influence of TV.