TL;DR version of a very long post: Oliver has a shot. Many countries ranked ahead of him will likely be entered, but those rankings are unreliable -- he'd probably around the 5th or so ranked guy there. And as Roar has said, he needs to make the finals since there will be no True 3rd match.
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The details:
The following countries are qualified at 65 kg -- with UWW seeding rankings:
1 - Russia - Rashidov
2 - India - Bajrang
3 - Kazakhstan - Niyabekov
4 - Hungary - Muszukajev
5 - Japan - Otoguro
10 - Mongolia - Tumur-Ochir
17 - Argentina - Destribats
34 - Senegal - Diatta
N/R - Azerbaijan - Aliyev (note, Rahimzade ranked 15)
N/R - Armenia - Tevanyan
N/R - Cuba - Valdes
N/R - Yazdani (note, Maghsoudi ranked 19)
N/R - Krgyzstan - Akmataliev
N/R - Tunisia - Dakhlaoui (note, Jelassi ranked 35)
The following countries have yet to qualify:
6 - Bahrain
7 - Ukraine
8 - Turkey
11 - Belarus
13 - Guinea-Bissau
14 - Ecuador
16 - Germany
18 - Nigeria
20 - Peru
21 - France
22 - North Korea
23 - Puerto Rico
24 - USA - Oliver
25 - Egypt
26 - Algeria
28 - Uzbekistan
30 - Brazil
32 - Poland
33 - Taipei
36 - Dominican Republic
T38 - South Africa
T38 - Venezuela
40 - Morocco
Notes:
- UWW rankings are based upon results at "Olympic Seeding events" which are very limited (IIRC only 5 events can generate seeding points) -- so these might not be representative of an analyst ranking.
- Skipped numbers indicate countries with multiple ranked wrestlers.
- Of the unqualified countries, the highest ranked wrestler is listed (too lazy to look up wrestlers for every country!)
- No idea which of these countries will send a rep to Last Chance Qualifier in Bulgaria -- or if that rep will be the highest ranked guy (for example, Oliver is not the highest-ranked American).
Zain and Yianni were both ranked, so one can reasonably say that Oliver is too low at 24. A more reasonable extrapolation might be around 12 -- in which case, he's right in the mix to qualify.
Of the countries ranked above 12th, Ukraine, Turkey, and Belarus are traditional powers.